GYMSIM - The mobile network for the yachting community

Frequently Asked Questions

Colin Squire Photo
Photo by Colin Squire
Glossary of terms
What is a SIM card?

Subscriber Identity Module. A SIM card is a special micro-chip which a user inserts into their GSM mobile phone. The SIM card gives the user a telephone number, and allows the user to connect to the network of the SIM card. The SIM card can be used in any unlocked GSM mobile phone.

What is “Roaming”?

Roaming is the process of taking your mobile phone away from its home country and travelling worldwide – your phone will not be using its own network anymore but will be “Roaming” on the networks of the country you are in. Roaming is normally very expensive, with high costs for outgoing calls, incoming calls, Sms Text messages and Data.

What is GSM?

Global System for Mobile Communications. It is the worldwide dominant Telecoms standard for mobile phones and networks. GSM was born in Europe and has now spread to over 85% of the global mobile market. GSM is the only system that give decent roaming capability, other competing systems have limited roaming.

Competing systems include CDMA as used in the USA, (GSM is also used in the USA) and W-CDMA as used in Japan exclusively.

The GSM standard uses four different radio frequencies, or “Bands” to cover the world.

What are Radio “Frequencies” or “Bands” ?

GSM uses four bands in its frequency spectrum, these are then grouped together so that the same two frequencies are always used together in a region or country. Generally speaking there are two bands to cover the European region and most of the rest of the world, and there are two other bands used by the USA and Canada regions and a few other American countries.

Generally a mobile phone is designed to only pick up the bands of its region, so a phone bought in Europe will not be able to pick up any networks in the USA and thus will not work there. The opposite happens for USA phones in Europe. Phone manufacturers have created a solution to this; it is possible to purchase “Tri-Band” phones and “Quad-band” phones. These phones work in all regions of the world to give maximum Global frequency compatibility. Although Tr-Band phones are adequate, Quad-Band phones can pick up one more Band then the “Tri-Band” phones, and thus are the preference for a global traveller who need maximum coverage worldwide.

Click here for more information about “Bands” and what phones work in which countries.


What is Gymsim?

Gymsim is a global GSM Mobile Telecoms provider. Gymsim uniquely offers a special low cost “Roaming” service on a Pre-paid Sim card that is designed to be used when travelling globally

Why Use Gymsim?
To save money. Our rates for using your phone while travelling (roaming) are very low, much lower then other regular networks. Our rates can even be lower then using local country specific Sim cards for calling locally.

This means that no matter where you travel in the world, you will be able to stay in contact with the outside world, and have one number where you can always be reached all at an affordable price.

Who should use Gymsim?

Our service is designed and tailored for the needs of Boat/Yacht crew. Yacht Crew are a community of people who travel/cruise regularly/permanently worldwide, regular local Sim cards are generally not suited to the needs of Yacht Crew.

Can anyone use Gymsim?

Yes, Gymsim would be useful for anyone who travels regularly, wants to stay in contact with the rest of the world and wishes to save money.

What kind of savings can be expected?

For Europeans: Within Europe average savings of 40%-60% can be expected compared to standard networks. When travelling globally, savings increase dramatically to 70% - 85%.

For non Europeans: The service can save 70% - 85% off your regular roaming rates wherever you travel.

These figures sound excessive, but with normal networks charging approximately 1.00 - 2.00 Euros/min for incoming and outgoing calls in many global destinations including the Caribbean, compared to Gymsim with outgoing calls of 0.29 Euros/min with Free incoming calls in many of these same destinations, including the Caribbean, then the advantages are clear.

What do you get when you buy a Gymsim.

You are purchasing a Global Pre-paid SIM card. Simply place the SIM card into an unlocked GSM mobile phone to connect to our network.

Your Sim card will come with its own number which you can then hand out to all your contacts. No matter where you travel in the world you will always be reachable on this number.


General Service information
Is it possible to connect to the internet with Gymsim?

Yes, You can connect to the internet at low cost with the highest speeds using your Gymsim. We have two different Sim cards:

  1. The World 44 Sim: This has Voice, SMS and Data compatibility. This Sim is for Mobile Phone use.
  2. The Global Data only Sim. This Sim only does Data, it is not Voice capable. It is designed to be used in Data only devices such as iPads and other Tablets, 3G Dongles for use with PC and MAC, and Mi-Fi devices (3G to Wi-Fi), and directly into specially equiped mobile PC's with built in 3G modem. PC's with builtin 3G modems.
For Data rates of both Sims please see the Rates page

How Many countries does Gymsim work in?

Gymsim works in over 215 countries. We have one of the largest Global footprints of any network provider. We have agreements with most networks in all countries - 750 networks. This means the best coverage with the best call quality. For a full list see the rates and coverage page.

What country does the Gymsim number come from?
Gymsim is from the UK, using the country code +44. It is a regular UK Mobile number. (It is not a personal or premium number).

How much does it cost to call TO a Gymsim mobile phone.

Calling to a Gymsim phone is the same as calling to any regular UK mobile number. (It is not a personal or premium number). The cost for this will depend on the provider you use, but generally it will be about 0.08 - 0.18 Euros per minute from a land line or VOIP line.

How can Gymsim be so cheap to use?

We heavily discount our rates by reducing our margins. Our goal is to make using your mobile phone as affordable as possible while travelling on a regular to permanent basis, this generates high levels of call traffic volume, and generates profit.

We also use technology called “Central Hub Calling” (CHC) Some may know of a similar system called “Callback” although the CHC process is now programmed onto the Sim card to make it fast and completely seamless to operate. It takes just a few seconds longer then normal to make a call and it offers substantial savings: To make a call you dial your destination number, 10 seconds later you receive an incoming call from our Central Hub, you answer this call and you will then be connected to the destination number at very low rates.

Incoming calls are answered as normal. Texting is also normal.

This technology is also useful as it gives us the ability to offer features such as free incoming voicemail messages, and Free or very low cost call divert.

Can I see how much my calls are costing me?

Yes, you can go online to the Gymsim website and see in real-time all calls you make or receive, and all text messages.

Are there any monthly bills, or minimum fees or other hidden costs?

Gymsim uses Pre-pay billing, so there is no contract, no monthly bills, no minimum fee and no hidden costs involved. For further information about rates please see the rates sheet, and if there is a surcharge rates sheet with it then also take note of this.

Which language does the Gymsim website and Gymsim card operate in?

English is the language used for all aspects of our product and website.

Is it possible to connect to the internet with Gymsim?

At this stage it is not possible to connect to the internet through Gymsim. This is a feature we expect to launch in the near future.

Is it possible to port my current number to a Gymsim card?

No, unfortunately number porting is not possible to or from the Gymsim network. This means that you cant take your current number and use that as a Gymsim number.

Can I send SMS text messages?

Yes, text messaging, both receiving and sending globally is possible.

Does Gymsim have voicemail?

Yes voicemail is already active with the Sim card, you do not need to set up a password to use your Voicemail.

Does it cost me anything to Receive voicemail messages?

No. Uniquely, we do not charge customers when messages are recorded in their Voicemail box. With other roaming phones you will be charged a high surcharge for this service.

How much does it cost to call voicemail to listen my messages?

The cost of calling to your voicemail to listening to recorded messages will depend on the country you are in. Please check the rates sheet (Click Here)

Can I listen to my Voicemail from an outside line?

This will soon be possible. You will need to set up a password for this facility.

Does Gymsim have Call Divert / Call forwarding?

Yes Gymsim has Call divert, it is a very useful tool for reducing costs when roaming :

  • If you are spending some time in a country with very high roaming costs.
  • If you are not using your Gymsim for a long period of time.
  • If you are staying in one country for a long period.
  • Returning home after your travels and don’t want to use your Gymsim at home but want to keep receiving calls on your Gymsim number (because all your contacts have your Gymsim number).

In all these situations it may be cheaper to purchase a local Sim card and divert all incoming Gymsim calls to the local Sim card.

The cost for diverting calls is either free or very low. The cost will depend on the country you are diverting to, and if it is a mobile or land line number. Please see the rates sheet for costs (click here)

Those calling you will never know the call is being diverted to your local Sim, it is as seamless and fast as a regular incoming call. It will not cost the caller any extra for this call. Essentially, we are just sending the call from our central Hub to your local Sim card instead of your Gymsim. Incoming text messages will not divert.

Does Gymsim use low cost / low quality Voip routing?

No, we use British Telecom for routing our calls. BT is a Tier 1 operator and arguably the highest quality routing provider. Our call quality is thus the best possible.

Does Gymsim work in places like Japan and Korea that do not have GSM networks, and only have W-CDMA networks?

Yes we have agreements with the networks of these countries, but a GSM phone will not function here. You will need to rent or purchase a local W-CDMA phone and insert your Gymsim card into this phone to gain access.

Can Gymsim work on the non GSM networks in the USA, like Sprint?

Yes, we have an agreement with Sprint, which is a CDMA network. You will need to rent or purchase a special CDMA phone that has the ability to accept SIM cards.

Is all my personal information I give Gymsim secure?

Yes, the Gymsim website database is fully encrypted with the latest SSL security.

Does Gymsim share its customers personal Details?

No, we do not sell or give out any of our customers personal details to any third parties. Customer information is used for Gymsim troubleshooting purposes only.

Is it possible to manage multiple Sim cards from a central account.

It is possible to manage all Sim cards from one central account. Simply add the additional SIM’s required to your account and it will be possible to manage everything from Top-ups for all Sim cards can be purchased, receipts for all purchases recorded, call costs can be viewed, Credit Cards managed for purchases etc.

Is it necessary to have personal ID, or other proofs of person when buying a Gymim card?

No, unlike other Sim cards, the Gymsim card is completely anonymous. No ID is required to own a Gymsim card – it is thus not possible for anyone to know the true identity of a Gymsim card owner. This is useful for those who wish to remain anonymous in their day to day lives.


Adding call time (Topping up)
How do I add call time to my phone? (Top-up)

Gymsim uses a Pre-paid billing system, that is you have to add funds (Top-up) to your Sim card to make calls. The amount of money you add will give you a relative period of talk time. To top-up your phone simply access the internet and then go online to Payments require a Visa credit/debit card, or a Mastercard.

. Receipts for all payments are emailed to clients, and also kept on file on customers “My account” page.

Are Payments secure?

The Gymsim website uses the strongest security systems available, and includes a few of our own anti fraud devices. All purchases are secure using the latest SSL encryptions


Once Auto-Top-Up is initiated, it does not require access to the internet to continue topping up. Payments with this system cannot be intercepted, thus making it the most secure way to Top-Up your phone.

Note: In general, it is not recommended to make any purchases from internet Cafes, or use a 3rd party Wifi connection as these have the potential to be insecure. This is especially true in less developed areas/countries. Our Click-to-Top-Up system helps to prevent this fraud, with Auto-Top-Up being the safest system. (Setting up a credit card for the first time should be done from a secure location). Although not manned 24/7, Customers can also contact the Gymsim support line to make a payment, or set up Click to top-up or Auto-top-up.

Is there an easier way to purchase top-up?

We also have an Auto-top-up system that gives clients the ability to let the Gymsim website add top-ups to their account automatically when their call credit drops down to a minimum pre-stipulated amount. Billing is then automatically done using the customers on file credit card for the payment, and top-up automatically added to the customers account. This facility is closely monitored with purchase receipts being sent to the customers email address, and recorded on customers “My Account” page.

Note: A top-up can only be triggered at the end of a call. This must be taken into account to prevent running out of credit in the middle of a call if your balance was already low.

For security reasons only one Auto-Top-Up is allowed per day. This must be taken into consideration when setting how much credit you want added to your account when the Auto-Top-Up triggers - to prevent running out of credit on a day of heavy use (It is still possible to do a manual Top-up)

Do I get a receipt of my purchases?

Yes, Receipts are generated immediately after all successful payment and sent to the users email address, a copy is also kept in the users “My Accounts” section. Payments that have failed will also generate a failed receipt.

If receipts do not arrive in your email inbox then check your Spam box. It is important to set and to your contacts list or set to “safe” so that these receipt emails and critical service updates will not be sent to your Spam box


Costs / Billing information
What are the costs of using my Gymsim?

This will depend on the country you are calling from, and the country you are calling to. We have a call calculator, and a rates table that can be printed out to view the call costs. Click here for details

Are there any connection fees?

There is a connection fee per incoming call and per outgoing call of 0.09 Euros per connected call. This is not a per minute fee, it is only charged one time when the call is answered. Please see rates list for up-to-date details (Click here)

What are the billing time increments?

All billing is done in 60 second increments.

Are there monthly fees or minimum usage fees associated with using Gymsim?

There are no monthly fees or minimum usage fees.

When does the billing start during a call?

When you call a number, you first will receive the callback and then you will be connected to the destination number. Billing only starts when the destination number answers your call.

There is an exception; If you are in a country that has an IOT surcharge, then you will be charged from the moment you answer the callback. Please see the rates list to identify the IOT countries

How long does my call credit last if I don’t use it?

Your Sim card will last for 16 months before it expires. Your top-up will last for 6 months before it expires. Simply top-up once (of any value) within those periods to extend the expiry times for a further 16 months for Sim card, or 6 months for top-up.

What name will I see on my Credit Card statement for purchases made to Gymsim?

Gymsim is the trading name for Global Mobile Ltd. Registered in Gibraltar. On customers credit card statements this is what customers will see.

Depending on the customers bank, the statement may also abbreviate the name to “GloMoLtd” or “Telecoms” or other similar variations, all from Gibraltar.


Country call cost information
Why are there still some expensive countries?

Some countries have very high wholesale rates to call to/from their networks, the level of which can be caused by the cost of setting up and running their service. Lack of competition in a country also creates higher rates and some networks collaborate with each other to increase rates.

Additionally, some networks in some countries have additional charges called “IOT” (Inter-operator Tariff). This is a charge that is generated either for increasing margin and boosting profit or to protect their market. As the network sets the rate directly, it affects all phones roaming on these IOT networks equally. It cannot generally be avoided. The charge only affects phones actually roaming on the network that charges IOT. It affecting both incoming and outgoing calls, but does not affect calling to the country from overseas. An example of an IOT country is the USA – cheap to call to the USA, but expensive to use in the USA.

All IOT charges are either already incorporated into the rates table, or will be indicated on a separate sheet that will accompany the rates table. Please click here for the rates page.


Lost Sim Card
If I loose my SIM card, is it possible to get a new SIM card with the same number again?

Yes this is possible. When a Sim card is lost or stolen, crew will be able to report this simply using a “Lost Sim” button in the My account page, this makes it simple to order a new Sim which will have the same number and the same top-up as the original. It will take about 2 days to create the new Sim, plus delivery time.


Backup Sim

It is possible to order a second Backup Sim card direct from the Gymsim website, this spare Sim card should be kept in a safe place in reserve. If crew loose their main Gymsim phone then just call us and we will transfer the number of your original SIM to your Backup SIM including all credit. This process will take less then 24 hours to action, and is free of charge.


General Mobile Phone Requirements
Can Gymsim work with any phone?

Our service works with the vast majority of GSM Mobile phones around the world. However, due to software differences within the GSM telecoms standard, not all phones can be compatible with all Sim cards – this includes Gymsim.

Incompatibility problems can range from the phone not functioning at all with the Sim card, to smaller issues with individual non critical functions of the phone or SIM not working correctly. Models of phones constantly change and models of the same type of phone but built in different countries can also cause problems, thus it is not possible to keep an up-to-date list of incompatible phones.

Your Phone must also be unlocked / SIM lock Free so that it will accept any SIM card from any Manufacturer. Please read below:

SIM locked phones

When purchased, most phones will be locked so that it will only function with the SIM card the manufacturer supplied with the phone. You can check if your phone is SIM locked by inserting a different SIM card into your phone - If you get one of the following messages, your phone is probably locked:

Unlocking a SIM Locked Phone

It is possible to unlock a SIM locked phone in four ways:

  • Contact the network the phone was supplied by, tell them you are travelling overseas and need to use a different SIM card in your phone. They will unlock your phone at a price.
  • Go to an independent phone store, they will usually have the necessary equipment to unlock most phones immediately.
  • Search the internet for “Mobile phone unlocking” websites. They will be able to unlock your phone by selling you a special unlock code that you input into your phone. (Example
  • Purchase a new unlocked phone.


General SIM Delivery Information
Make your purchase in good time

If your yacht will soon be leaving its address soon, do not make a last minute purchase giving only 1-2 days leeway. SIM cards can be delayed longer then the approximate delivery times.

SIM’s that are not delivered will generally wait at the local delivery depot for a few weeks before being returned to us, we can only send a replacement SIM when the original SIM returns to us. The re-sent SIM will be free of charge, but delivery costs will be charged.

Signed to be received

Most of our delivery options require the SIM card to be signed to be received. Please ensure this is possible with your destination address. SIM that are not signed will generally stay at the local depot for a few weeks before being returned to us.

For those that are sending to an address where a SIM card cannot to signed for, we can offer a first class service, but the SIM is then not insured against loss, thus the customer will be responsible for the costs of re-ordering a new SIM.

Some of our Priority registered countries do not requiring signing for, information about these can be found here.

Accurate Delivery address

The delivery address of a destination must be 100% accurate. At Gymsim, we or the delivery service are not responsible for SIM cards undelivered due to inaccurate address, and so a new SIM will be replaced only at full cost to the customer

Crew are urged to:

  • Double check that the address being used is 100% correct, get a second opinion if required.
  • Double check spelling is correct, and that the way the address is arranged is correct to local standards.
  • If being delivered to a Yacht, always include the name of the yacht and not just the Marina.
Holidays and weekends – “Working Days”

The postal services do not normally work on weekends or public holidays. SIM cards can therefore not be posted or delivered at these times.

Additionally, SIM’s will not be transited on weekends, so delivery times only consider “working” days and not weekends or holidays.

Delivery Delays

It is possible that delivery delays occur. The indicated delivery times for a SIM to arrive are approximate. If a destination is easy to reach in a large town/major city, delivery times will be fast. If the delivery is going to an-out-of-the-way destination that is difficult to get to, then delivery times will be on the long side. Upon this, delays are possible, the frequency of delays will depend on the destination country – the less developed the country or region, the higher the frequency of delays.

SIM “Lost in Transit”

Sim cards may on occasion go missing in transit. The frequency of this will depend on the country – the less developed the country the higher the frequency of SIM’s being “Lost in Transit” Registered and Insured Sims are replaced immediately at no cost to customer.

What to do about a delayed or lost SIM

If a SIM card does not arrive within the approximate allotted time then first double check that the SIM is not simply misplaced at the destination address, or if someone else (in your crew) hasn’t picked the SIM card up already. If this is not fruitful, then please give delivery another two days to account for any delays, checking the destination address every day, and then contact us at with all orders details.

If a SIM card is “lost in transit” and was sent using a registered delivery service, we will re-send a new SIM card without delay. Customers who order their Sims using unregistered post will need to replace the Sim at their own cost.

SIM cards sent to Agents or Marinas

SIM’s sent to Agents or Marinas may be misplaced by their staff.

  • Always make sure that the offices are able to sign to receive goods for the crew or yachts.
  • Make sure you include your Yachts name, and your name clearly in the address.
  • It is recommended to take the name of someone reliable working in the Agent or Marina office. Either have the SIM card delivered C/o to their name, or make sure this person is aware the SIM will be arriving, at what approximate date, and if they will be able to
  • Check regularly for your SIM card before and after expected delivery time, be a pest so your SIM will not be forgotten.

Delivery Options

All deliveries will go out same day if the order is received before 1pm UK time.

Delivery times are working days only. Delivery services do not operate on weekends or public holidays. Note, registered deliveries to the UK are possible on a Saturday, but it is not guaranteed.

  Standard Delivery
Not registered, Not insured, Not tracked. Only to be used when it is not possible for anyone to sign to receive post at the destination address.
Registered Delivery
Registered, Insured. Fully tracked to most major destinations (signed to receive not required) Partially tracked to other destinations. (signed to be received required)
Registered, Insured, Fully tracked to all destinations. Very fast and reliable to most destinations. Signed to be received. We subsidise by 30%
UK 2 Working days

1 Working Day
(Guaranteed before 1pm, Sign to receive)

Western Europe 5-7 Working Days 3-6 Working Days 1-2 Working Days*
Eastern Europe 6-8 Working Days 4-7 Working Days 1-2 Working Days
USA & Canada 7-10 Working Days 5-8 Working Days 1 Working Day
Good Value, fast - Strongly Recommended
Australia & New Zealand 7-10 Working Days 5-8 Working Days 2-3 Working Days
Caribbean 14-21 Days
Deliveries are delayed and go missing regularly – not recommended
14-21 Days
Deliveries are delayed and go missing regularly – not recommended
2-3 Working Days
* *Very reliable & fast - Strongly recommended
Rest of the World

7-28 Working Days
Note - The speed and reliability depends on the developed level of the country the Sim is sent to.

6-28 Working Days
Note - The speed and reliability depends on the developed level of the country the Sim is sent to.
1-5 Working Days
Note - The speed and reliability depends on the developed level of the country the Sim is sent to.

* In certain European areas FedEx only use agents and so a delivery may take a little longer. Such examples are Palma which takes 2 days delivery, Additionally, some European destinations have poor postal connections and infrastructure in these few places a delivery can take substantially longer, a notable example is Sardinia which can take 4 days.

** We use yacht agents in St Marten and Antigua which can expedite delivery, and hold SIM cards as long as required. Our Agents are central to marinas and will be known to most crew - crew thus do not need a local address to send their Sim and they wont have to go far to pick them up. Crew can also order the Sim before they reach their Caribbean destination so it will be waiting for them on arrival. We recommend that crew purchase SIM cards together to share the cost of the FedEx.

Within delivery times are normal guidelines, to large towns and cities the delivery will be faster then to more rural destinations. To the even more out-of-the-way places the delivery may take longer then the quoted figures above, it may be possible for general delays to occur.

It is possible for any delivery to go missing in the post. The occurrence of this is less in the more developed countries, and more in the lesser developed countries. Registered deliveries are insured and so are immediately replaced without additional cost, deliveries not registered are not insured and so can only be replaced at the cost of the customer.

We are not responsible for any non deliveries due to inaccurate or incomplete addresses. Crew will be charged additional cost to have a replacement Sim sent out.