International Call Letter Prefixes

Search by country, by call sign prefix (e.g. J4), or by MCC (e.g. 208) — all in one box.

Census “100+” = more than 100 (2023). No MCC issued = country has call sign prefixes but no DMR country code.

Country / Territory	MCC	2023 Census	Call Sign Prefixes

Prefixes the ITU Does Not Issue

A few call sign prefixes will never turn up against a country above, because the ITU either holds them in reserve or bars them outright. They fall into two groups.

Unallocated — held in reserve for future use

These series aren't assigned to anyone yet, but the ITU could allocate them later:

E8, E9, H5, J9, S4, V9, YZ, 4N, Z4–Z9,
On → O2, O3, O4, O5, O6, O7, O8, O9
Un → U2, U3, U4, U5, U6, U7, U8, U9
Xn → X2, X3, X4, X5, X6, X7, X8, X9

Unavailable — never issued, by rule

1A – 1Z — the entire 1-series is reserved and unallocated (which is why unofficial calls like 1A0 for the Order of Malta and 1S for the Spratlys are heard but not officially recognized).
QA – QZ — no prefix may begin with Q; it would be confused with the Q-codes.
Digits 0 and 1 — no prefix uses these numerals, because 0 looks like the letter O and 1 looks like the letter I. (This is exactly why the reserve series above run from 2 to 9, not 1 to 9.)
Two-digit prefixes (a digit followed by a digit) are not assigned by the ITU.