You can use Zisland Explorer

Predicts genomic islands based on the segmental cumulative GC profile. Zisland Explorer was designed with a novel strategy, as well as a combination of the homogeneity and heterogeneity of genomic sequences.

more can be found here

Download page and documentation

Or EGID

Utilizes the prediction results of existing computational tools, filters and generates consensus prediction results.

you can use the tool island viewer. its efficient in prediction of genomic islands.