The mobile number prefix 0931 or +63931 in the Philippines is primarily associated with Sun Cellular, which has been integrated into Smart Communications.
However, with the implementation of the Mobile Number Portability (MNP) law, subscribers can switch networks without changing their mobile numbers. This means a number starting with the 0931 prefix, originally assigned to Sun Cellular (now under Smart), could now belong to a different network if the user has ported their number.
