Key Points:
- SIM cards typically feature between 8KB and 256KB of stored data, including your phone number, contacts book, and Subscriber Identity PIN number.
- Talkmobile's SIM Only plan gives you the option of a physical SIM or an eSIM.
- No other data, such as applications or media, is stored on a SIM. That is instead handled by your phone's internal (or external) storage options.
SIM cards have changed a lot over the years, with them getting sleeker and smaller just as smartphones have gotten more advanced. Now we've even got eSIMs, which fully remove the need for a physical SIM card in the first place. With that said, what's actually on a SIM card? We're going through what data is stored, how it's used, and everything you need to know to get the best experience from a Talkmobile SIM Only plan in 2026.
How much is stored on a SIM card or eSIM in 2026?
While the size and formats of SIM cards have evolved into 2026, what's actually stored on them has remained the same since their inception. Both physical SIM cards and eSIMs store an incredibly small amount of data, ranging from just 8KB to 256KB. This may not sound like much, but it's enough to hold your phone number, your Subscriber Identity pin, and your contacts, of which the average SIM card or eSIM is believed to be able to store up to 250 names and numbers.
In other words, all that's stored on an eSIM or physical SIM card these days is just enough to verify your number, keep all your contacts, and help you connect to your provider to call, text, and use mobile data services like 4G and 5G easily.
Aleksha's Advice: Whether eSIMs or physical SIM cards, the only information held amounts to just a handful of kilobytes, just enough to verify to your network provider that the phone is legitimate and to give access to a service.
How SIM cards changed throughout the years
| SIM size | Description | Dimensions | Introduction Year |
| Standard | Developed in 1991 and used in old mobile phones. | 85 mm x 53.98 mm | 1991 |
|---|---|---|---|
| Mini | Replaced the larger SIMs, phased out by the late 2000s. | 25 mm × 15 mm | 1996 |
| Micro | Replaced Mini SIM as the more popular alternative. | 15 mm x 12 mm | 2010 |
| Nano | Most common SIM for phones without eSIM support. | 12.3 mm x 8.8 mm | 2012 |
| eSIM | Embedded into device PCB; non-removable. | ~5 mm × 6 mm (or less) | 2017 |
What's not stored on a SIM card in 2026?
Now that we know what's on an eSIM or a SIM card, it's important to know what isn't included, namely any applications you may have downloaded as well as any media available, such as photos, videos, or music. These are stored on your mobile phone's internal flash storage, or external storage card, such as a Micro SD card, if it's compatible. As a result, you can think of an eSIM or a SIM card as a validator, a license key that lets you use your phone, validating it for your services.
Does removing your SIM card or eSIM from your phone delete everything?
eSIMs and SIM cards are essentially licenses to text, call, and access mobile data. As such, removing a physical SIM card from the tray or deleting an eSIM won't purge your data, but you won't have access to your contacts book, be able to validate your phone number, or access network services without it, until it's reinstated or reinserted. Fortunately, eSIMs handle all this information differently, as a phone can swap between them from a dedicated SIM manager on iOS or Android, so there's no need to fret about replacing or upgrading an eSIM, even if you change phone numbers; the handset itself makes a copy of this information, and contacts can be synced with your respective Apple or Google account, too.
