Elladan and Elrohir will be welcome aboard the Wave-hunter, if they can be convinced to join your crew.
'Queen Arwen's brothers? Aye, they spoke of tracking down Corsairs who might have hidden after the raid upon Tûm Rost. I do not know exactly where they might have gone since, but you should begin your search for them somewhere near Iáphel.'
Elladan and Elrohir went in search of Corsairs near Iáphel, intending to find any of the raiders who might have hidden after the attack.
Elladan and Elrohir will have returned to Ost Arndír by the time you get there.