I want to copy a mini sim card to a micro sim card, how do I do it?

June 16, 2013 2:11 PM

I have an aging smartphone that I'd like to replace with a different unlocked smartphone I intend to buy. The old one uses a mini-SIM, the new one has a micro-SIM slot.

Can you talk me through the steps (even if the steps include purchasing a commercial sim card reader / writer off ebay somehow) of doing this and any pitfalls to avoid? Would I still need to purchase some sort of generic SIM kit from the carrier which I'd configure with the copy information? Are SIM cards imprinted with the carrier info like ethernet devices are imprinted with manufacturer info in the MAC address? If so, are there any 'generic' multi carrier SIMS that work? Things like that are what I'm interested in.

I fully realize that cutting your SIM card is easier, but I'm more interested in copying if only for learning how all the pieces fit together.

posted by Feel the beat of the rhythm of the night to Technology (8 answers total)

Best answer: I believe you want to look up cloning the SIM card. This is not intended to be user-doable and the carrier (any carrier) will not help you and may be upset if they figure out you've done it (for instance, if you let both SIM cards contact the network at the same time). 'Newer' SIM cards (2000+) apparently have some traps to them that risk wiping it when you try and extract the data as well. There's plenty of discussion online, but I have no idea how up-to-date/valid they all are.
posted by jacalata at 2:45 PM on June 16, 2013

You can use SIM readers to copy phone numbers and other stored information but you can't really copy the secret keys that identify the SIM to the network. This is by design. There are ways to do it, especially with very old SIMs but it's complicated and definitely not carrier endorsed. In some places it is actually illegal.
posted by atrazine at 2:47 PM on June 16, 2013

As far as I know, this is not possible.

SIM cards are smart cards with a microprocessor, an operating system, and a file system. The SIM card readers you see on ebay are for accessing certain directories in the file system (like the address book) but can't access the higher levels for bit-for-bit copying without the cell phone provider's transport keys, which are kept secret. Apparently, the levels of encryption n SIM cards used to be weaker, so they allowed cloning and multiSIMs, but this is no longer the case in most parts of the world.
posted by bluecore at 2:49 PM on June 16, 2013

I actually just did this through my carrier (T-Mobile). I bought a phone online that needed a micro SD but my phone had a mini.
I went to the store and told them I bought a new phone that needed a mini SD and they did everything there in 5 minutes for free.
They did an awesome job of copying EVERYTHING. not only did my contacts transfer, but also my alarm settings, my saved Wi-Fi connections, bookmarks, apps, settings, etc.
Hopefully this is an option for you.
posted by simplethings at 3:20 PM on June 16, 2013

Lots of phone repair shops(look for WE FIX IPHONES! Places) will have a tool that cuts a mini sim into a micro sim. This is what you want.

Cloning is hard, and generally not worth bothering with.
posted by emptythought at 3:39 PM on June 16, 2013

When I moved to my new phone that uses a micro-SIM, I cut my old sim card to the required dimensions using a sharp knife (following a random guide on the Internet) and it worked fine. Of course there is a risk with doing this, so you may be better off getting it cut with the tool for that purpose as emptythought suggests.
posted by Gomez_in_the_South at 5:47 PM on June 16, 2013

simplethings: an SD card is not the same as a SIM card.
posted by jacalata at 2:05 AM on June 17, 2013

Response by poster: Thanks everybody!
posted by Feel the beat of the rhythm of the night at 9:48 AM on June 17, 2013