Lehane spent four seasons at Cork City, making 33 first team appearances.
However, the 21-year-old found opportunities limited and manager John Caulfield sent him on loan to Sligo Rovers last July.
Now Cobh will hope the former Douglas Hall man can score the goals to get them out of the First Division.
Meanwhile, former Limerick striker Rory Gaffney has regained his League of Ireland form resulting in two League Two clubs squabbling over his future.
Gaffney joined Cambridge United from Limerick last September after scoring 19 times in 17 games, but he could not repeat that form with Cambridge, hitting the net twice in five games before moving on loan to Bristol Rovers at the end of November.
The clubs verbally agreed a deal in principle that Gaffney could join Rovers on a free transfer in January but Cambridge appear to have changed their minds after the Tuam man netted five goals in seven appearances for Rovers.
Gaffney reported back for training in Cambridge yesterday and will wait for the two clubs to forge a deal that is likely to involve a transfer fee now.