Country code +688 (dialed as 00 688 from many places) is Tuvalu.
All numbers are 5 digits after country code +688.
(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.)
The telephone country code for Zimbabwe is +263. The area code for Chakari is 0688, or +263 688 in international format.
Leichtenstein is telephone country code +423.
where is telephone country code 1816
That is not a country code.
The country code and area code of Fraile Muerto, Uruguay is 598, (0)688.
Country code +57 is Colombia.
Country code 52 is Mexico.
Fiji has telephone country code +679.
Gibraltar is country code +350.
Moldova is country code +373.
Slovenia is country code +386.
Vanuatu is country code +678.