Dolphin and St Mary's both managed to pick up bonus points but both are relegated with Galwegians sealing the fate of the Templeville Road side thanks to a 19-13 victory over Brent Pope's side.
In Division Two, Old Belvedere dropped from first to fourth after they were blitzed in the opening half by UL Bohemians - who led by 24 points - at Thomond Park and Dublin University took full advantage gaining full points with a 34-3 over Sunday's Well to earn themselves division one football next season.
Division One: Belfast Harlequins 19-0 Ballymena Dolphin 6-13 Blackrock CollegeDungannon 3-9Buccaneers Galwegians 19-13 St. Mary's College Garryowen 15-14 Co. CarlowLansdowne 18-0 Cork Constitution U.C.D. 0-21 Clontarf.Shannon - Free.
Division Two: Barnhall 17-5 Ballynahinch Dublin University 34-3 Sunday's Well DLSP 20-0Malone
Division Three: Ards 0-11 Instonians Connemara 9-3 Banbridge Greystones 31-10 Naas Highfield 26-17Corinthians Old Wesley 3-28 Wanderers Queens University 3-12 Clonakilty Skerries 33-13 Portadown Suttonians 9-19 City of Derry.