Andrea Spendolini-Sirieix marked her senior European debut with mixed synchronised 10m silver alongside Noah Williams in Budapest.
The British pair achieved a total of 307.32 points from their five routines with Ukraine (325.68) taking gold and Russia (302.58) finishing third.
"It's an amazing result and I'm so grateful," the 17-year-old said.
"I was exhausted after all the travel and competition, but this is a great ice-breaker for the event.
"I'm looking forward to my individual (event) later in the week."
The teenager, who was the Young Sports Personality of the Year award winner in 2020, strengthened her case for an Olympic place by finishing an impressive fourth in the individual 10m platform event at the Diving World Cup last week.
Spendolini-Sirieix and Williams were late additions to the competition in Budapest, with team management deciding to give them experience in the venue ahead of their respective individual events later in the week.
"Things were looking a little shaky during practice as we'd only had an hour together, but we managed to pull it together in the competition," said Williams.
"It's not been easy for anyone, having over 14 months out of competing, but it's great to be back at an event like this which feels really safe as well."
Williams, 20, will have his chance to state his claim for a place at Tokyo 2020 - with Tom Daley - when he competes in the European individual 10m event on Sunday.
In the women's 1m springboard final Britain's Katherine Torrance finished ninth in an event won by Elena Bertocchi of Italy.