What is phone number 999-999-9999?

Answer 1

It's a bogus telephone number.

If 999-999-9999 showed up on your Caller ID display, most likely one of two things happened:

• a transitory technical glitch caused the Caller ID data to get scrambled en route, or
• you got a call from a telemarketer or a scammer who "accidentally misprogrammed" their telephone equipment to send bogus Caller ID data.

There is no area code 999 in North America (USA, Canada, etc.), nor in the UK. There is no telephone country code +999 (reserved for some unspecified future global service).

In Mexico, area code 999 is Mérida, with 7-digit local numbers, so +52 999 999 9999 could be a valid number. If it's a mobile phone, the number would be dialed as +52 1 999 999 9999.

(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.)