Calling codes

The trunk prefix is the actual trap

The country code is the easy half. What catches people is the trunk prefix — the digit dialled inside a country before an area code, which must be dropped when dialling in from outside.

A London number written locally as 020 7946 0000 is +44 20 7946 0000 from abroad. Not +44 020. The leading zero is a domestic instruction, not part of the number, and including it means the call fails.

Most of Europe and Asia uses 0. North America uses 1, which happens to be the same as its country code. Hong Kong has no trunk prefix at all, which is why Hong Kong numbers look identical whether written for local or international use — one of the few places where nothing has to be removed.

Taiwan, Hong Kong, Macau and China are four different codes

+886, +852, +853 and +86 respectively. They are separate numbering plans, and a call between any two of them is an international call charged as such.

Dialling from Taiwan to Hong Kong means 002 (or another carrier prefix) then 852 then the number. Taiwanese carriers use different international access prefixes — 002, 005, 006, 009 — which route through different carriers at different rates for the same call.

+, 00, 002, 011

The + is not a digit. It is a placeholder meaning “whatever this country’s international access code is”, and a mobile phone substitutes it for you.

Dialling manually you need the real prefix: 00 in most of Europe and Asia, 011 in North America, 002 and others in Taiwan.

Store numbers with +. A number saved as 020 7946 0000 will not connect when you are abroad; saved as +44 20 7946 0000 it works everywhere, including at home.