Police have linked more than 500 crimes to the use of dating apps Tinder and Grindr, including murder, rape and child abuse.
Almost a third of these were sexual offences including rape, child abuse and grooming.
It comes after serial killer Stephen Port was jailed last month for the murders of four young men, including Daniel Whitworth, he met on gay websites and apps including Grindr.
Lib Dem leader Tim Farron warned: “I worry that these shocking figures could just be the tip of the iceberg.”
Data compiled by almost three-quarters of police forces across England and Wales listed 523 crimes from the past five years where official logs included the words Tinder or Grindr.
Tinder launched as a smartphone app in 2012 and Grindr, used largely by gay and bisexual men, in 2009.
Among the highest incidences of crime linked to them, 98 were recorded by the Met Police, 58 in Greater Manchester and 49 in Merseyside.
Across the country officers reported at least 162 sexual offences, including 63 rapes, linked to the two apps.
And the Freedom of Information data from 31 of the 43 forces suggests incidences related to the two dating services are surging. This year alone, Greater Manchester Police recorded 12 rapes linked to the apps – two were logged the previous year.
Lib Dem leader Tim Farron said: “The real figures could be significantly higher.” He added: “While many people have found their perfect match through these dating apps, there are those who have became victims of horrific crimes.
“The police need to do much more than they currently are to highlight the real dangers of online dating.”
Forces also reported several sex attacks on children plus cases of grooming, child sex abuse and child prostitution. Thefts, assaults and harassment were commonplace.
Chief Constable Simon Bailey, national lead for violence and public protection, said: “The rising popularity of online dating apps and websites has contributed to an increase in the number of recorded crimes. I would urge those who use online dating apps to be as security conscious as possible.”
A Scotland Yard spokesman added: “The Metropolitan Police Service works hard to bring offenders to justice and we advocate using apps safely and encourage the reporting of crime as soon as possible.”