UK adults spent a quarter of their online waking day during the blockade - a record, according to Ofcom.
In April, adults spent an average of four hours a day online, compared to half past three in September 2019, according to the communications watchdog.
And seven out of 10 people made video calls at least once a week during the blockade, with millions turning to Zoom for the first time.
The pandemic has fundamentally changed online behavior, Ofcom said.
The regulator's online nation report found that people are looking for new ways to stay connected, informed, entertained and fit during the blockade.
Twitch, the livestream platform for gamers, saw visitors increase from 2.3 million in January to 4.2 million in April.
TikTok, which allows users to create and share short videos, reached 12.9 million visitors to the UK in April, up from 5.4 million in January.
Much of the Ofcom report focused on people's online habits in September 2019, before the coronavirus hit.
At that point, nine out of 10 adults and almost all children spent time on platforms like TikTok, YouTube, Snapchat and Instagram, according to the study.
And almost half of adults watch videos on these platforms several times a day, going up to 73% for children aged 8 to 15.
People are no longer just passive consumers, with two out of five adults uploading videos to TikTok, YouTube, Snapchat or Instagram.
The video conferencing app Zoom demonstrated the block's great success, going from 659,000 users in January to 13 million in April, when the nation turned to it to chat with family and friends and take part in quizzes and games.
The app was not without controversy, with questions about how safe it was, with some people falling victim to the zoom-bombing, in which an uninvited guest joins a call to cause malice or share unpleasant or hateful material.
Radical change
Even before the pandemic, people were moving away from landline calls and text messages in favor of WhatsApp and Facebook Messenger, the report said.
The blockade appears to have accelerated the adoption of these services. Almost half of UK adults have used WhatsApp to make video calls at least once a week, with Facebook Messenger not far behind with 41% and Apple's FaceTime used with 30%.
Ofcom's director of strategy and research, Yih-Choung Teh, said: "Lockdown could leave a lasting digital legacy. Coronavirus has radically changed the way we live, work and communicate online, with millions of people using online video services for the first time. "
People continue to be wary of online security, with 87% of adults claiming to have concerns about children using video-sharing websites and other apps.
