Three out of four children aged under five have access to a computer or mobile device, according to a study.
Research by Childwise found that more than 50% of pre-school children have their own tablet or computer.
The amount of time spent watching TV and online video content has risen from 2.6 hours in 2017 to 2.8 hours.
YouTube was named as the most popular app across all age and gender categories in the report, with boys watching for longer than girls.
Childwise research manager Jenny Ehren said: “The increasing use of connected devices by pre-schoolers this year may reflect growing access to on-demand services, especially subscription-based options such as Netflix which has quickly risen through the ranks over the last three to four years.
“Their list of favourite programmes is becoming more varied, and whilst many are drawn from across the different pre-school channels, we are beginning to see more references to content exclusively available on YouTube and paid-for streaming services.
“This year has seen a noticeable increase in gaming with three out of 10 under-fives now regularly exposed to video games, often as players, but also as spectators as well.”
The research discovered increased interactions between pre-school children and virtual assistants such as Siri and Alexa.
Childwise said more than two-thirds of pre-school households own a gadget that uses voice recognition, and more than a quarter of under-fives have used voice recognition software.
According to the report, CBeebies remains the most popular TV channel among the age group, but content from subscription-based services such as Netflix and Amazon Prime have “gained significant ground this year”.
Original content from YouTube, predominately nursery rhymes and educational viewing, also appeared in the list of pre-schoolers’ favourite content for the first time.
However, the report also discovered an increase in offline activities among pre-school children, with a rise in the number of under-fives doing arts and crafts and going to the library.