The city is surrounded by water and has more shores than one could wish for, thanks to its borders with the Sea of Marmara, the Golden Horn and the Bosphorus. But if you want decent beaches in Istanbul and unpolluted water you have to go to the Marmara Islands (Marmara and Avsa are the main islands), about two hours away on the high-speed hydrofoil sea buses or six on the standard ferries. An archipelago in the Sea of Marmara, the islands have nice beaches, but are a major summer destination for holidaying locals who can’t afford to go elsewhere. So it’s best to go either end of the holiday season, from late June to mid- September. During the season the high-speed hydrofoils leave from Bostanci (10am on) and Yenikapi (10.30am on) to head for the Marmara Islands. Ferries leave from Eminönü (8.30am on). Alternatively see Buz Ada in the Swimming section below.