I have never managed to learn a phonetic alphabet, although it would be useful on the phone. But I know where to find them! In the Dark Ages I used to use the lists in the back of the two-volume Langenscheidt dictionary known as the big Muret-Sanders. But for some years I have used this list on the Internet, from Brian Kelk in Cambridge. Here is a very small part of it:

bq. The NATO phonetic alphabet:
Alpha Bravo Charlie Delta Echo Foxtrot Golf Hotel India
Juliet Kilo Lima Mike November Oscar Papa Quebec Romeo
Sierra Tango Uniform Victor Whiskey Xray Yankee Zulu
[This alphabet dates from about 1955 and is approved by the
International Civil Aviation Organization, the FAA and the
International Telecommunication Union; note that different
bodies prefer different spellings, so one also sees:
Alfa Juliett Juliette Oskar Viktor]

bq. [The alphabet above is from the Cambridge Encyclopedia of
Language. An alphabet with Alfa X-ray can be found in The
U.S. Department of Defense Dictionary of Military Terms.
Alfa Juliett X-ray, which is the ICAO version, appears in
A Concise Dictionary Of Slang And Unconventional English
and also two Langenscheidt dictionaries]

bq. [There is one report of UK police using Indigo instead
of India.
German army handbook 90/91: Alfa Foxtrott Juliett.
Italian version: Alfa Charly FoxTrot Giuliet Romio Wiskey.
An Indonesian phrase book: Beta Ultra Volvo Whisky X-ray.
A precursor of the present alphabet (1952?) had: Alfa Coca
Metro Nectar Siera Union Whisky Extra]

Actually, there’s a better version at Kelk’s own site. Better because it contains what Kelk calls ‘further material’. It contains superb links and also ‘silly alphabets’. This includes a group attempt to create the world’s worst phonetic alphabet, and a version of the Cockney alphabet:

bq. ‘Ay fer ‘orses
Beef or mutton
Seaforth highlanders
Deaf or dumb
‘Eave a brick
Effervescence
Chief of police
‘Ate yer for it
Eye fer an eye
J fer oranges
Kafe fer a cuppa
‘Ell fer leather
Emphasis
N fer a penny . . .
Over my dead body
Pee fer a penny
Q fer the flicks
‘arf a mo
S fer me
T fer two
Euphemism
Viva la France
Double you for it
Wife or girlfriend?
‘s ‘ead fer ‘s ‘at

Here’s another list, but it seems to lack the international ones.