Avon and Somerset Police say 85 crimes were reported within the first 48 hours of the Glastonbury festival opening its gates on Wednesday morning. That's a 30% decrease on last year.
About half of these were property thefts, with 30 people arrested so far.
Police said they used tracking software to locate one stolen phone and arrested a woman overnight.
Inspector Liz Hughes, of Avon and Somerset Police, said: "Thanks to a tracking app, we've been able to recover a stolen phone, which shows that they really do work."
"They are really useful and I would urge anyone who hasn't already got one installed to do so today."
"We've also arrested three men on suspicion of theft and this shows that there are a very small number of people who come here intending to steal and spoil the fun for everyone else."
"While the arrests are a positive step, it's a reminder to us all to look after your possessions very carefully."