Which country code is 00923?

Telephone country codes never begin with zero.

Country code +32, dialed as 00 32 from many places, is Belgium. A number beginning with +32 3 is a landline in Antwerp, Sint Niklaas, or surrounding areas.

Country code +23, dialed as 003 23 from many places, is an incomplete code in Africa. You need one more digit to determine the country.

To avoid confusion, it is best to write an international telephone number in correct international format, beginning with the plus symbol and the correct telephone country code (e.g., +32 or +238), omitting any dialing prefix.

(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.)