Trearddur Bay first appears in the 1933–34 Anglesey League, finishing level on points with champions
Llangefni. They appeared again after
World War II. Trearddur Bay again appear in the league from 1980 until withdrawing during the 2000–01 season. Trearddur Bay United joined Saturday league football for 2008–09, and saw success in their first season, winning the
North Wales Coast FA Junior Challenge Cup as well as the Anglesey League's Dargie Cup and Thomas & Williams Cup. The following season saw them obtain more cup success, retaining the Dargie Cup and winning the Elias Cup. The 2010–11 season saw them win the Anglesey League and three cup competitions, and gain promotion to the
Gwynedd League. The club's first season saw them finish league runners-up and win the Cwpan Gwynedd. The following season they went one better and finished champions of the league, gaining promotion to the
Welsh Alliance League Division Two. The club finished third in the first season in the league and third again the followings season, gaining promotion to Division One. The next season saw the club win Division One at their first attempt but they were denied promotion to the
Cymru Alliance, as their ground did not meet the required criteria to qualify for promotion. In June 2017 a new management team of former manager, Chris Davies and Nathan Owen took over. The following July the club withdrew from the Welsh Alliance League, planning to take a year out. In August 2019 the club merged with
Bryngwran Bulls to form
Trearddur Bay Bulls. This was a short lived affair and the club once again folded in 2020. The club finally combined its three sections into one (ladies, juniors, men's) and relaunched under the one heading of Trearddur Bay Football Club. The club has grown and now offers football to Boys, Girls, The disabled and senior men's. The club returned to senior football for the 2022–23 season and were crowned champions of Division One of the
North Wales Coast West Football League followed by back-to-back wins becoming Premier Division champions in the 2023–24 season. This gained them promotion to the
Ardal North West. Campbell Harrison took over as manager in May 2025. Footage has circulated on social media of their player Tom Taylor elbowing
Porthmadog player Danny Brookwell On 22 January 2026 it was reported that secretary Chris Davies left the club, but says it was unrelated to the incident. Taylor will appear in court on 11 May 2026. In March 2026, manager Campbell Harrison left the club, with them 10th in the Ardal North West. He had led the team to its first ever
Welsh Cup quarter-final. ==Honours==