Where is telephone country code 881?

Country code +870 (dialed as 00 870 from many places) is used for Inmarsat satellite phones, including ship-to-shore.

Note: charges for calling +870 are substantially higher than most international calls.

(Inmarsat previously used +871, +872, +873, and +874 for satellite phones in specific parts of the world, but those codes have been retired in favor of the single code +870.)

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)