The total number that had gambled online was up 3% at 21%, and 56% of those online gamblers had more than one online account, with an average of three online accounts for every participant.
Total gambling participation in Great Britain rose 1% from 2018, with 47% of respondents confirming they had gambled in the past four weeks.
This figure dropped to 32% when excluding those who had only gambled on the National Lottery draws.
The National Lottery draws remained the most popular gambling activity, while football and horseracing were the most popular sports betting activities.
The proportion of respondents who had seen a gambling advertisement on television in the past week was down 3% at 51%.
However, trust in the industry was down, with 43% of participants associating gambling with crime, up 5% from 2018, and 29% believing gambling to be fair and trustworthy, down 1% at 29%.
The report was based on quarterly telephone and online tracking surveys conducted by Populus on behalf of the Gambling Commission.
The latest data from the NHS Digital Health Survey for England estimates a current national problem gambling rate of 0.5%.