All three clubs from the southern premiership - Mosgiel, University and Caversham - are fully committed to the South Island league although they will have a fair wait to kick off in the competition.
The final round of the premiership, which is sponsored by the Otago Daily Times, was played on Saturday, with Mosgiel winning the first round of the league. It drew 1-1 with University.
Caversham also confirmed at least third courtesy of its 5-2 win over Northern.
There had been speculation not all teams would want to play in the South Island league. The three top teams will play in the South Island league along with five teams from the Mainland federation.
The South Island league started only last year with the idea to try to raise the standard of football right across the South Island.
Mosgiel president Dave Young said Mosgiel fully intended to play in the South Island league. It had qualified so it wished to push on and compete.
The success in the southern premiership was just reward for some hard work by the club. A new coach in Cam McPhail and better focus by players had combined to get the club to the top of the league.
It was the first time since 1996 that Mosgiel had tasted league success. Dunedin Technical and Caversham had been dominant over the past 20 years.
It was also a rags-to-riches story for University which, like Mosgiel, has missed out on being in the top three last year.
Coached by Darren Hart, the side had been in the top reaches of the competition all year. With the University of Otago celebrating its 150th year, it was apt the side reached the top three. It was well down the ladder last season.
Caversham had a down year last season but under new coach Richard Murray has climbed back up the premiership.
The side could go second - University is one point ahead - as it has a catch-up game to play against Green Island next Monday.
The game between the sides had to be abandoned in April after a player was badly injured.
Murray said it was a big commitment for the club to play in the South Island league but it was keen and the players wanted to be involved.
He had come in as coach this season and with a change of culture and a better attitude results had improved.
The South Island league was run on an equalisation basis so all eight teams contributed the same amount of money.
With Nelson likely to be in the mix, the total amount to be paid was yet to be finalised but it was expected to be at least $10,000.
The Mainland competition, made up of eight teams, was playing two rounds before it split. Five teams from Mainland played in the South Island league.
The South Island league will not kick off until June 29 as the Mainland league still has a few rounds to go.
That will leave the three southern clubs with no league football for a month although there are two rounds of Chatham Cup to be played.
Queenstown, Dunedin Technical and Southland made the South Island league last year.
