However, the package of supports falls short of what was recommended earlier this year by the Oireachtas Committee on Education.
There are five post-primary schools on islands off Donegal and Galway and between them they cater for almost 230 students.
Education and Skills Minister Richard Bruton said each school would get an extra €15,000 in annual funding to cover their additional running costs.
The teacher allocation is to be raised from one extra teacher to the equivalent of one and a half from September.
Mr Bruton said he was acutely aware of the “challenging environment” in which island post-primary schools operate and the additional resources were being made available to meet their “unique circumstances”.
One school, Coláiste Naomh Eoin on Inis Meáin, Co Galway, is to be granted independent stand-alone status. The school opened in September 2003 under the auspices of Coláiste Colmchille, Inveran, Co Galway, and County Galway Vocational Education Committee.
The change in status will mean that the school will have its own principal and deputy principal and a board of management.
However, a report published by the Oireachtas Committee on Education last February recommended that school budgets be increased by at least €20,000 to reflect actual running costs.
It said the additional costs incurred by schools for travel, school outings, cargo costs and school repairs should be recognised in an additional allocation in school budgets. It also recommended the reinstatement of an allowance for teachers in island schools that was removed in 2012.
Giving back the allowance would recognise the additional challenges and costs for those teaching in an island school, the report stated. Because of the additional costs for travel and accommodation falling to teachers, schools were finding it difficult to find and retain staff.
The report’s publication followed a campaign by island communities and educational representatives to highlight the unique challenges that the schools face.