The GB Rowing Team won the women's competition and were runners-up in both the men's and overall standings when the 31st edition of the Coupe de la Jeunesse took place in Szeged, Hungary over the weekend.
Britain's overall medal haul of 16 - four gold, seven silver and five bronze - was matched only by Italy, who won the European team competition for under-18s for a second successive year.
Apart from the women's eight, who traditionally open the regatta on Friday, there were races on both Saturday and Sunday for the British crews.
Team manager Jimmy Scragg said: "It was particularly pleasing how the team as a whole stepped on from the Saturday to the Sunday, which shows what a good learning experience the Coupe can be for these young athletes."
The four gold medals were all claimed by Britain's dominant women, who recorded a top-five finish in every race.
Gloucester Hartpury's Alice Bowyer took first place in the women's single scull on both days, edging out Italy's Emma Isabel Torre by less than a second on Saturday before recording a comfortable winning margin on Sunday.
The women's quad of Lola Anderson, Robyn Armstrong, Lucy Glover and Izzy Lingard also bagged two gold medals, winning both their finals in impressive fashion.
The GB women's eight got the competition under way on Friday by winning silver behind Belgium in a tight finish, just three-tenths of a second separating the two crews after an exciting race.
The women's pair of Tilly Catlin and Holly Wicklow were runners-up to Italy on both days, while the four of Kelsey Stoddart, Alex Slabbert, Lydia Currie and Georgia Mulraine improved from bronze on Saturday to silver on Sunday.
In the men's competition, there was a brace of silver medals for the coxed four of David Bewicke-Copley, Harry Higginbottom, Alex Slater, Francois Gouws and cox Akil Hashmi.
The men's double scull of Rory Harris and George Lawton won silver on Sunday, having been fifth the day before, while Oli Dix took a bronze medal in the second single scull final of the weekend.
The men's eight won bronze medals on both days, while the men's four of Will Stewart, Dom Jackson, Bertie Woodward-Fisher and Oskar Arzt-Jones were third on Saturday and fourth on Sunday.
All of the British crews reached the A final during the course of a highly-encouraging weekend, which was a step on from last year's results in Libourne, France, where GB won one gold, two silver and nine bronze medals.
Next up for GB Rowing Team's under-18s will be the World Junior Championships, which get under way in Rio de Janeiro, Brazil this week.
All nine GB Junior boats will start their campaign with heats on Thursday, starting at 12.30pm BST (8.30am in Rio).