Belgrade is situated at the confluence of the rivers Danube and Sava.

The river Sava flows across the region through Slovenia, Croacia and Bosnia, until it meets the waters of the Danube in Belgrade. Here, it crosses the city from South to North. Central Belgrade lies at the right bank of the river.

The Belgrade river banks are 200km long. There are 16 river islands on the Belgrade waterways of which the most well-known are: Ada Ciganlija and Veliko ratno ostrvo (Great War Island).

Ada Ciganlija is a former island on the Sava river, and Belgrade's biggest sports and recreational complex. Today it is connected with the right bank of the Sava via two causeways, creating an artificial lake. It is the most popular destination for Belgraders during the city's hot summers. There are 7 kilometres of long beaches and sports facilities for various sports. During summer there are between 200,000 and 300,000 bathers daily. Clubs work 24 hours a day, organising live music and overnight beach parties. Extreme sports are available, such as bungee jumping, water skiing and paintballing. There are numerous tracks on the island, where it is possible to ride a bike, go for a walk or go jogging.

Great War Island is located at the mouth of the Sava river into the Danube. The Island covers an area of 2.11 km². It is low, for the most part marshy and often flooded by the Danube. Currently some two-thirds of the island are used as a nature preserve for 196 bird species, many of which are endangered. One of Belgrade's beaches, Lido, is located on the northern tip of the island.