Why do Taiwan mobile numbers drop the leading 0 when written as +886?

Question

Weirdo · Accepted Answer

The leading 0 is a domestic trunk/prefix digit; it disappears in the international +886 form. Locally you write 0912-345-678; internationally it’s +886 912 345 678—not +886 0912…. Keeping that extra 0 is a common reason SMS and overseas dialing fail.

Inside Taiwan, the leading 0 on area codes and mobile prefixes (02, 09, and so on) is the domestic trunk/network prefix. Once you add country code +886, what follows is the national significant number itself—without repeating that domestic 0.

ITU-T E.164 defines international numbers as “+” + country code + national significant number. Taiwan’s country code is 886. A mobile written as ten domestic digits starting with 09 becomes +886 plus nine digits starting with 9. Landlines follow the same rule: 02-xxxx-xxxx → +886 2 xxxx xxxx.

When a form asks for an international mobile, enter +8869xxxxxxxx. An extra 0 yields an invalid length or a wrong route; dropping the leading 9 is equally broken. Storing contacts in international form usually saves the most pain for roaming and overseas OTP delivery.

Why do Taiwan mobile numbers drop the leading 0 when written as +886?

0 is a domestic prefix, not part of the international number

How E.164 assembles it

How to write it in forms and contacts