I'm lost. Can you help me?
PER-so — stress on first syllable. ai-u-TAR-mi — stress on third syllable.
The essential phrase when you are completely disoriented and need help.
'Mi sono perso' (I'm lost) is reflexive passato prossimo — 'perdersi' (to get lost). The feminine form is 'mi sono persa'. 'Può aiutarmi?' (can you help me?) is a polite request. This phrase will always get a sympathetic response from Italians.
Non trovo la mia strada.
I can't find my way.
Alternative expression for being lost
Credo di essermi perso — dove sono?
I think I got lost — where am I?
Adding uncertainty makes it more natural
Non so dov'è questo indirizzo.
I don't know where this address is.
When you have an address but can't find it
Getting lost in Italian historic centres is almost a rite of passage — and often leads to wonderful discoveries. Italian locals are almost universally willing to help lost tourists. If you ask directions and they seem uncertain, they will often consult a neighbour or call out to someone nearby rather than admit they don't know — Italians take the duty to help very seriously.