Jersey rounded off their greatest ever season with a 23-8 win over Fylde, before being presented with the National One trophy.
Two penalty tries put the islanders on course for victory in front of 3,454 fans at St Peter.
Nick Royle touched down in the closing stages but it was too little too late for Fylde.
The islanders had already clinched promotion to the Championship with a game to spare after beating Coventry.
"It's been a fantastic season and the boys are rightly very proud of themselves," said Jersey director of rugby Ben Harvey.
"There's lots of smiles as you can imagine and I'm delighted for them all.
"It's just great to think that next year people who come and watch games on this island will watch future internationals.
"To think that our lads can compete with that, and I would back our lads to do well, is a phenomenal achievement."
Jersey stalwart Steve O'Brien and forward Jim Brownrigg were both making their last appearances for the club before retiring.
"I've been very lucky to play with some wonderful players since I've come to the island," O'Brien told BBC Radio Jersey.
"It's very special, to take the club to the Championship is a very nice feeling."
Fylde, who looked like challenging for the title for much of the season, finished in fourth spot in the National One table.
Jersey finished seven points clear of second-placed Ealing Trailfinders.