What Is a SIM CardSIM stands for Subscriber Identity Module. It is a removable card inside a cell phone that stores user data. This data informs your card provider who you are and enables you to connect to the provider's wireless network. And since it holds your data, you can transfer the mobile SIM card from phone to phone to access the same provider network and maintain the same phone number. Your contacts won't know you switched phones.
A person holding a SIM cardWithout the SIM card, you cannot make phone calls, send text messages, or access data. You can only access the internet via WiFi/mobile hotspot.
Physical SIM Card vs. eSIMIf you buy a new cell phone, you need to transfer your old-size SIM card to the new device, which might not fit. Your provider can use a SIM swap tool to get a compatible size SIM or update your phone's digital eSIM. An eSIM is the easier option because it eliminates the physical SIM card size compatibility issues. It is a chip inside your phone that providers can update online. So setting up a new phone, switching networks, or swapping SIM cards requires a quick download to complete
A phone with an eSIM cardAdditionally, it is plastic-free, which is good for the environment. And it leaves the physical SIM card slot open, enabling you to insert a separate SIM card to run two numbers on your phone, like a dual-sim phone. However, only a dual-sim compatible device can run the eSIM and physical SIM concurrently. But not all phones can use eSIM connectivity because it requires compatible devices, and there are few compatible phone models, especially Android phones. So the physical card option is the only one available to most users.
SIM Card SizesSIM cards come in three sizes.
- Standard: Introduced in 1996, these are the largest SIM card sizes and fit in older devices like the first iPhones (3GS), Samsung Galaxy Note/S, and Blackberry Curve. They measure 15 x 25mm and also go by the name of mini SIM cards.
The three SIM card sizes
- Micro: These SIM cards are smaller than the standard type but not as tiny as the nano size. The cards were the ideal size for about ten years after their introduction in 2003. Phones like the Samsung Galaxy S5 and iPhone 4S had micro SIM card slots. They measure 12 x 15mm.
- Nano: Nano SIM cards are the tiniest in dimensions and thickness (the cards measure 8.8 x 12.3mm). They came into the market in 2012 and are typical in most modern smartphones, including the iPhone 5 going upwards.
What Is a 3-in-1 SIM CardThe three standard, micro, and nano options come as pre-cut SIM card sizes and can only fit in compatible cell phones. But a 3-in-1 SIM card contains all three sizes in one. So you can insert it into an old or new phone without using the SIM swap tool due to compatibility issues.
A person inserting a nano SIM card into a smartphoneThe "triple-cut" SIM card is a nano SIM card with two adapters. One expands its size to fit a micro SIM slot, and the other adds a larger plastic card around the original SIM card to match the standard SIM slot. Regardless of the phone generation, the pins or connectors in the SIM slot are the same. So a nano sim can work in a standard SIM slot, provided it is in the correct position. That is where the adapter comes in.
Different SIM card adaptersThe adapters are tiny, non-aging plastic pieces that enable you to convert your nano SIM to a micro or mini SIM by adding some plastic around the perimeter. A nano SIM fits somewhere in the middle and gets positioned in a way that will contact the pins in your phone accurately in the slot. In a nutshell, a 3-in-1 SIM card adapter is a card frame for an incompatible SIM card that simplifies installation by enabling you to punch the SIM into the correct frame tool-free for accurate sizing.
A nano SIM card with a micro SIM adapter that can fit into a standard SIM adapter
Can I Insert Any SIM Card Type In My Device?It depends on your phone or tablet. If you want an eSIM, you must have a compatible device. But if you want a physical card, the 3-in-1 (Triple) SIM card or card frame will work.
The three SIM card sizesBut remember, switching SIM cards to another carrier network is only possible if you have an unlocked phone.
Can You Run Three SIM Cards On Your Phone?This ability also depends on the device. Running three SIM cards means having a dual SIM card ready feature plus an eSIM chip built in. Some phones have these features but can only operate dual SIM networks.
A dual SIM phone with a two SIM card trayBut some devices, like Galaxy S20, can run three networks. This phone features an eSIM plus two SIM slots, one of which is a hybrid. So you can run three mobile carrier networks or two plus one Micro SD card.