Yes you can, up to 16gb. Take a backup of the whole pen, replace the sd card, which is located below a flap, under the batteries, Then copy the backup onto the new sd card. If you lose the beeps and clunks then you will need to install a new subdir folder, so please contact us and we will send you a link to download it. 02084455123.
PENfriend 3 now has 16GB as norm. This has been the case since beginning 2022.