This is a list of transfers involving clubs that played in the 2010 League of Ireland Premier Division and 2010 League of Ireland First Division.
The pre-season transfer window opened on 1 December 2009, and closed on 22 February 2010 for domestic transfers, and on 2 March 2010 for foreign transfers.
Players without a club may join one at any time, either during or in between transfer windows.
In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Out: In: Kevin McHugh from Linfield F.C.
Out: In: Out: In: Out: In: Out: In: Out: In: Out: