All smartphones, tablets, and some older laptops use a SIM card to connect to a mobile network and to enable mobile broadband services. However, these devices need SIM cards of different sizes and types. Below, we will explain those sizes and types.

A Brief History of the SIM Card and Different SIM Card Sizes

SIM (Subscriber Identity Module) cards have been around since 1991 when the European Telecommunications Standards Institute introduced them to identify and authenticate mobile phone users and subscribers. The first SIM cards were the same size as the standard credit or debit cards used today, but that size would only remain the standard for a little while.

The standard SIM card that was a staple of the 2000s was introduced in 1996, and it was a lot smaller and more convenient than the SIM card of the past. The smaller SIM cards started the race for smaller mobile devices because manufacturers no longer had to make space accommodations for the larger SIM cards.

These days, micro and nano-SIM cards are the norm, especially in smartphones. The Apple iPad and the iPhone were among the first to use this new SIM card size, with the iPhone 4 being the first smartphone to use a micro-SIM.

The nano-SIM is the current standard used in most modern smartphones. There has recently been a push for embedded eSIMs that do not use a physical card. The eSIM is embedded directly into the device and authenticated by whatever carrier you use. It is also more secure because no one can get hold of your SIM card to clone it, which has caused many problems in the past.

The SIM Card Chip

Although the SIM card chip has become more capable and secure in recent years, it has remained the same regardless of the SIM card size. For this reason, the size of a SIM card depends on the amount of plastic around the main chip.

The chip is responsible for storing different types of data, including information about your phone number, authentication, and contacts if you enable the option.

Different SIM Card Sizes: The Standard SIM Card

While it is no longer the “standard” SIM card for today’s devices, the standard SIM card size was the only option when it was launched, hence its name. The standard SIM card is also the largest one, and its size is 15 by 25 millimeters. Because it is the largest SIM card, you could consider the other smaller SIM card sizes the cut-down versions.

The standard SIM card was used in notable smartphones such as the iPhone 3GS, but it is no longer used in modern smartphones. However, you can still find it in budget and feature phones that are common in developing countries. It is also used in older laptops that require a mobile connection and broadband, as well as some handsets that are remnants of a past era.

iPhone SIM Card Sizes: Micro SIM Cards

The micro-SIM card was introduced in 2003 by the European Telecommunications Standards Institute (ETSI) as a new SIM card size standard. It was developed as a smaller alternative to the standard SIM card, the most used SIM card size at the time. It measures 12 by 15 millimeters.

The primary goal of the micro-SIM was to reduce the size of mobile devices, which was becoming increasingly important as smartphones and tablets began to gain popularity. The smaller size of the micro-SIM allowed manufacturers to design smaller, more compact devices while still providing the same functionality as standard SIM cards.

The micro-SIM was initially slow to gain traction, as manufacturers did not widely adopt it until the introduction of the first-generation iPad in 2010. The iPad was the first device to use the micro-SIM in a mainstream product, which helped establish the new SIM card size as a standard for mobile devices.

Since then, the micro-SIM has become the most used SIM card size in smartphones, including popular models such as the iPhone 4 and 4S, Samsung Galaxy S III, and HTC One X. In addition to smartphones, the micro-SIM is also used in tablets and mobile routers.

The micro-SIM has become less common as the number of devices favoring nano-SIM over this SIM card size has increased. However, many Android smartphones still use a micro-SIM card, but you will rarely find it in modern Android phones.

The Nano SIM Card Size

Nano-SIM cards are the smallest type of SIM card available today, measuring 8.8mm by 12.3mm. It is also the newest smartphone size as it was introduced in 2012. It has since become the most common type of SIM card used in modern smartphones.

The primary advantage of the nano-SIM is its small size, which allows device manufacturers to design even thinner and more compact devices.

One potential drawback of the nano-SIM is that it requires a special tray or slot to hold it. This is because there is almost no plastic border around the SIM card ship, making it difficult to handle while inserting into or removing from a device. Because of its minuscule size, we do not expect to see a smaller SIM card in the future unless the SIM card ship shrinks.

Its smaller size also means it may not be compatible with all devices, particularly older models designed to use larger SIM cards such as the micro-SIM card. However, most modern smartphones now use nano-SIM cards, including popular models like the iPhone 12, Samsung Galaxy S21, and Google Pixel 6.

A Combi SIM Card

This is not a SIM card size but a combination of all three sizes. The plastic around each size is scored so users can easily pop out the SIM card size they need. You can use the remaining SIM card as an adapter because you can use a bigger “adapter” to make the SIM card larger for use in phones that use a bigger SIM card size.

Note that some combi SIM cards do not allow you to do this, and it might require some fiddling to make your SIM card larger. Also, you might insert the SIM card into the “adapter” and have difficulty removing it if you reuse a combi SIM card.

Many mobile network providers send these SIM cards when you buy or request one, so they do not have to worry about sending you the right or wrong SIM card size. Lebara will send you a combination SIM card when you order their data-only SIM. Doing so will ensure you get the SIM card that is the exact match for your device.

Smaller Than Nano SIM Cards, the Embedded SIM (eSIM)

An embedded SIM card comes inside your device, so you cannot remove it. This type of SIM card has become the standard in many modern phones and is used in the iPhone 14 and Samsung Galaxy 22 lines.

These SIM cards are even smaller than nano-SIM cards, which frees up even more space inside devices, allowing manufacturers to make their devices smaller or make other components, such as the battery or main system on a chip, bigger. Their smaller size also means they are used a lot in smartwatches and other embedded devices that need a cellular connection.

The biggest benefit of a nano-SIM is the ability to switch carriers and network plans. Since there is no way to remove the SIM card – it is embedded – you need to have a way to change the carrier while keeping the SIM card you already have. Instead of swapping a physical card, you swap the data inside the eSIM to connect to a new carrier or a plan.

eSIMs are also a great option for people who travel internationally and who need to switch their numbers often. The main thing to remember is to check that the carriers in the country you are traveling to support the SIM band your device uses to avoid compatibility issues.

Another benefit is that you can program different numbers into an eSIM. Doing so allows you to, at least theoretically, own multiplier numbers and have all of them with you as long as you have your device with you without carrying multiple physical cards. You also do all this without dealing with all the SIM card sizes we discussed above.

While many more phones are adapting eSIM cards, they are typically used alongside removable SIM cards. This means you can get a data-only card Lebara for use in phones that support eSIM. Although the network providers who support them are few at this time, we expect them to become standard moving forward, just like the SIM cards that came before them.

Understanding the different SIM card sizes will help you get the right one for your phone. Today, you mainly only have to think about micro and nano-SIM cards, although numerous phones still use the standard or macro-SIM card size. Some devices support embedded SIM cards, so you do not have to worry about sizes or switching physical cards.