About 10,000 fans are expected to travel to the city without tickets
Manchester United fans are being urged to avoid Rome's tourist areas when they visit for the Champions League final.
The Foreign and Commonwealth Office (FCO) is warning the expected 30,000 supporters to stay away from areas where they may be targeted by gangs.
Supporters are advised not to take the metro to the Piazzale Flaminio or to use one of the Eternal City's bridges, the Ponte Duca D'Aosta.
About 10,000 ticketless fans are due at next week's game against Barcelona.
The FCO also issued guidance to stay "as far away as possible" from the Campo dei Fiori square, where there has been trouble in previous years.
Alastair Mackie, FCO sports liaison officer, said: "This is a once in a lifetime trip for many fans and we want them all to have a fantastic time but it is important to make suitable preparations before travel.
"We have been working closely with the Italian authorities and the British Embassy in Rome to ensure that fans have support in Rome and access to all the information they need to ensure a safe trip.
"We would encourage fans to visit www.fco.gov.uk/football before their departure."
Free transport has been organised to and from the Stadio Olimpico for official fans and between Villa Borghese and the stadium for independent fans.
Pierluigi Puglia, Rome Embassy press officer, said: "We have worked closely with the Italian authorities in preparation for the event and we appreciate their excellent co-operation in developing the necessary safety measures for British fans."
A 0-0 draw with Arsenal on Saturday gave United their 18th league crown, and equalled the record of rivals Liverpool.
Mayor Gianni Alemanno said: "Rome welcomes the British fans with open arms and we look forward to celebrating this great sporting festival together."