View the promotion/relegation format for the Connacht Junior Leagues here.
Galwegians went into the final day in the relegation play-off spot but a 30-23 win away to already relegated NUIG meant that Buccaneers needed a positive result away to second-placed Connemara.
Despite a brave effort, Buccaneers fell to a 32-27 loss and will now face Corinthians or Tuam as they bid to avoid the drop.
Champions Ballina collected the trophy after their 10-3 win away to Ballinasloe and Westport defeated Monivea 27-10.
A 51-10 win over Loughrea saw Sligo’s junior team crowned J1B champions after an outstanding campaign.
The hunt for second place is still on as Tuam defeated Creggs 18-0 to stay on track for second place and a promotion play-off against Buccaneers.
Ballina will face Corinthians in the J2 League play-off final after both sides upset the odds to record away semi-final victories.
Ballina defeated OLBC, who had claimed top spot in the league, in a thriller that ended 26-23 as the visitors scored two late tries to snatch victory. The other semi-final saw Corinthians also come from behind as they won at Oughterard.
J1A League: Ballinasloe 3-10 Ballina, Ballinasloe RFC; Connemara 32-27 Buccaneers, Monastery Field; NUIG 23-30 Galwegians, Dangan; Westport 27-10 Monivea, Westport RFC;
J1B League: Sligo 51-10 Loughrea, Hamilton Park; Tuam 18-0 Creggs, Tuam RFC;
J2 League Semi-Finals: OLBC 23-26 Ballina, OLBC; Oughterard 8-10 Corinthians, Oughterard RFC;