Smartphones are most likely to be stolen between noon and 5pm, according to research from Lookout, a mobile security company.
More than a third of survey respondents from the UK, France and Germany said they had been stolen from during the afternoon, while a quarter had been robbed between 5pm and 10pm.
Pickpocketing was revealed to be the most common cause of phone loss in the three countries, accounting for 28% of theft.
Lookout said: "Chances are, the sooner you discover your phone is missing, the higher likelihood you'll get it back. The golden hour after the theft occurs is key because, let's face it, thieves are sneaky."
Thieves can avoid being tracked by turning off the phone, switching it to aeroplane mode or removing the SIM card, reducing the chance of being caught.
The willingness of victims to chase thieves varied across Europe, with 89% of Germans claiming they would do so, while around 70% of British and French people said the same.
However roughly three quarters of victims did not notice immediately when their phone was stolen, offsetting the risk of "vigilantism", as the report termed it.