The expression 'friends forever' is translated into amici per sempre in Italian.
This type of phrase is often seen adorning everything from stationery cases to the backs of bags, and belongs in the realm of noisy classrooms and early afternoon children's television.
Other phrases to use about friends
Other handy phrases that you might use to describe a friendship that will last forever are as follows:
Firstly, you might only want to share these kind of phrases with your 'best friend' or migliore amica (pronounced mil-yor-eh am-eeka if she's a girl) or migliore amico (if he's a boy).
You may also want to decorate their notebook or diary with cute phrases that show how much you care for them, Italians have a really good abbreviation for this- they simply use TVTB which stands for ti voglio tanto bene (tee vol-yo tantoh bey-neh) and is something like saying 'I care a lot about you'. You could also use the more complex TVUMDB which is ti voglio un mondo di bene, and literally translates as 'I want a world of good for you'.
'Friends Forever' in Italian popular culture
The phrase amici per sempre was used as the Italian title for the 1995 US film 'The Cure', which told the story of two friends researching a cure for AIDS, whilst one of them was actually battling the disease. The expression is also the name of a song by the rather peculiarly named Italian group Pooh, a video clip of which is available on youtube. (Watching this link comes with a warning: Expect cringe-worthy haircuts and four men swaying in unison to the backdrop of zebras galloping.)