How to distinguish between SIM cards in a Dual SIM phone?

Question

The Dual SIM management interface at least under Android 10 is badly designed. With two SIMs inserted, esp. when they are of the same mobile operator, I struggle with quickly determining which status bar icon or SIM card list entry refers to which SIM card.

What best practices are available to help deal with this situation?

---

By "badly designed", I refer to these issues:

• The SIM card list in Android settings and the SIM icon list in the Android status bar do not make clear by which criterion they are ordered. They do not make any reference to the concept of a "first" and "second" SIM card, so it is not even clear if there is such a concept at all in Android.

• The freetext "SIM names" that one can assign to SIM cards in Android do not make clear if they are names for SIM cards or SIM card slots.

• At least for some SIM cards, the SIM info screen of Android does not list any information. Neither the card's phone number, nor the SIM card ID (a long number printed on the card), nor any other ID.

• When one connection type abbreviation ("4G", "3G" etc.) is written between the two signal strength indicator icons in the status bar, it is unclear if SIM1 (left icon) or SIM2 (right icon) has the active data connection. Of course, one could remember that the connection type always refers to the icon following it, but one will also forget again …

• On top, the layout of the SIM tray on some phones (e.g. Galaxy Note 9) is counterintuitive as the first SIM card is at the bottom, while in the Android UI, the first SIM card is always listed at the top. The tray has "SIM1" and "SIM2" written on it, but this is very small and easy to overlook.

Answer 1

The following process for installing and naming SIM cards in a Dual SIM phone helped me to identify SIMs clearly and quickly at all times. This refers to a use case when you want to use one SIM for mobile data and the other for phone calls. You may have to adapt that to your use case.

1. Place your data SIM into the SIM 1 slot. Insert the SIM tray into the phone.
2. Give your data SIM a SIM name "SIM1 Network-Name Data" in the Android settings. Obviously, change "Network-Name" to the name of your network operator, such as "O2" or "T-Mobile".
3. Place your phone SIM into the SIM 2 slot. Insert the SIM tray into the phone.
4. Give your phone SIM a SIM name "SIM2 Network-Name Phone" in the Android settings.

Why and how this helps

By inserting and naming one SIM card after the other in a two-step process, it becomes easy to identify which of the two SIM cards is which in Android, even if both SIM cards are for the same mobile network.

After naming SIM cards, you can in principle swap them in the SIM tray. The SIM names refer to the SIM cards and not the SIM slots, so swapping cards will change the icon position and position in the SIM card list, but will have no effect on the SIM card configurations. So after the initial setup, it would be easiest to always and only identify your SIM card by name in Android, forgetting about which card is in which slot. However, that is not recommendable because there is one exception that requires us to know which SIM card is SIM 1 and which is SIM 2: the signal strength icons in the status bar only use positions (SIM 1 left, SIM 2 right), not SIM names. Due to this, it is best to simply include the SIM number at the start of your SIM name (e.g. "SIM1 O2"). That also makes it clear that SIMs are ordered by SIM number in the SIM list, which is otherwise not obvious.

In addition, it is best to put the SIM used for data connections into the SIM 1 slot. This is because otherwise you'll be confused when trying to figure out to which SIM a single connection type identifier ("4G", "3G" etc.) refers when it appears in between the two signal strength icons in the status bar. The connection type identifier always refers to the icon following it, but you will forget that. Placing the data SIM into the SIM 1 slot makes it unnecessary to remember this, as the connection type identifier icon will then appear before the first icon, evidently referring to that first icon and not the second.

In addition, it can be a good idea to include the ending digits of the SIM card numbers in the Android SIM names, for example "SIM1 O2 Data #…5481. That makes it possible to make sure the SIM cards are in the trays they should be, even if both come from the same network operator. It also tells you which physical SIM card is meant for which use, without having to consult other notes in or out of the phone.