Bosphorus Tour

Throughout Sultanahmet, there are hawkers selling tours of the Bosphorus, ranging from 15 Eur a person to over 50 Eur, for trips with museum stop overs. In fact there seem to be more tour hawkers than carpet sellers! 

Istanbul's ferry operator also offers a Bosphorus tour, although in less glamorous boats (they use standard ferries), and their long tour is the only one I saw that actually traversed the majority of the Bosphorus Straight. At 25 Liras, plus 10 Liras for a GPS enabled audio guide, it's a bargain.

The trip starts at the Eminounu docks and calls at a number of docks along the way, before a 3 hour layover at Anadolu Kavağı.

Apart from the Bosphorus itself, there are a number of palaces and a few ruins to look at from the boat, which tracks the shoreline quite a bit. We even managed to spot a small school of dolphins - which is apparently very rare occurrence.