X-WATERS Belgrade

A former river arm of the Sava, sealed off in the 1960s, transforms Belgrade's riverbanks into an expansive open-water basin. Organized by X-WATERS, X-WATERS Belgrade is an open water swimming event hosted in this protected body of water at Ada Ciganlija in Belgrade, Serbia. For open water swimmers, the basin offers an ideal racing arena where the unpredictable river current is completely replaced by flat, serene freshwater. Stepping into the water at Taložnik beach, participants find a calm and clear lake course laid out right alongside the bustling lakeside promenade. The sheltered conditions make navigation easy and forgiving, whether you are tackling an open water sprint for the first time or looking to build up race endurance early in the year.

When the horn sounds, swimmers run straight from the shoreline into the water and follow a clockwise circuit marked out by guide buoys. The race lineup offers a distance for every goal, including a 500-meter dash, a 1-mile event, a 3 km race completed over three laps, a 5 km marathon covering two long loops, a 3x1 km relay, and a 100-meter children's showcase. An organizer's boat stays stationed at every turn buoy to keep your line true, giving you an unobstructed sighting perspective. Swimmers looking for an intense weekend can also combine events across the schedule, pairing the 1-mile swim with the 3 km or tackling the 5 km alongside either the mile or the relay. This flexible format builds on a racing tradition first brought to Ada Ciganlija in 2021, when international marathon swimmers gathered here to race nautical miles and endurance courses along the length of the lake.

Lake Sava: from turbulent river branch to inland basin

The tranquil racing surface of Lake Sava is the product of ambitious engineering that reshaped this stretch of the river. Between 1957 and 1967, construction crews dammed the former right arm of the Sava River, cutting off the heavy river flow. By constructing permanent embankments and an upper causeway during the 1970s, builders transformed what was once a shifting river island into a continuous peninsula firmly tied to the mainland. The resulting basin stretches between 4.2 and 4.4 kilometers in length, offering depths between 3 and 6 meters across an area of nearly a square kilometer. Underneath the surface, the lake bed transitions smoothly from coastal gravel along the edges to soft silt and sand across the deeper central trough.

While Belgrade winters often freeze the entire lake under ice up to 30 centimeters thick, by summer the enclosed waters warm up significantly, regularly reaching comfortable highs around 27°C (81 °F). Long before it became a premier destination for rowing, sprint canoeing, and long-distance swimming, this waterway was known as the Čukarica Arm. It was also along the bank of the Čukarica Arm that Serbia's first shipbuilding yard operated, constructing the nation's earliest steamboats and iron barges.

The flora, fauna, and secret wetlands of Ada Ciganlija

The placid conditions inside Lake Sava support a clean aquatic ecosystem where swimmers occasionally glimpse Craspedacusta sowerbyi, a delicate freshwater jellyfish that has thrived in the lake since at least 1994. These tiny, translucent white creatures only develop when water temperatures climb past 25°C (77 °F). Ada Safari is an intimate six-hectare natural lake with an average depth of around two meters. The site was originally a wild depression called Savska bara that flooded whenever the Sava River swelled, before being drained for a short-lived recreation project in the late 1970s and early 1980s. Left to return to marshland, the lake was thoroughly cleaned and restored in 1994, today resting enclosed within a dense, century-old floodplain forest.

This shaded sanctuary forms a haven for diverse wetland birdlife, drawing mallards, grey herons, kingfishers, and pygmy cormorants to its quiet banks. Further across the peninsula, a dedicated 21-hectare nature reserve protects rare woodland fungi, representing the only documented habitat in Serbia for the pepper-pot earthstar mushroom, Myriostoma coliforme.

Ada Međica and the flowing currents of the Sava

Just outside the sheltered lake embankment, the natural Sava River tells a completely different story. Directly in the open current sits Ada Međica, an oval river island measuring 1.5 kilometers long and 200 meters wide. Driven by the relentless power of the river current, the entire island actually migrates downstream by 50 to 100 centimeters each year, prompting locals to reinforce its western upstream tip with concrete to halt the erosion. Ada Međica can be reached by small river boats that shuttle visitors across from the riverbank. The island features two wild beaches—one concrete-lined bank at its northern tip and a sandy stretch down south—alongside stilt houses built above the reach of regular river floods. These silted waters hold echoes of river history, including an unexploded 50-kilogram bomb from World War II discovered eleven meters beneath the surface near the island's tip in 2016. It underscores how deeply modern civil engineering and seasonal calm have tamed the adjacent swimming basin.

Belgrade's summer coast along the promenade and splavovi

On warm race days, the lake basin of Ada Ciganlija acts as a natural oasis, feeling considerably cooler than downtown Belgrade thanks to the microclimate created by its extensive canopy, green woodlands, and open water. Swimmers and spectators spend entire days along the water's edge, where a ring of cycling paths, hiking trails, water sports, and shaded outdoor cafes frame the competition area. Just across the river on the left bank of New Belgrade, the Sava Quay extends for three kilometers along an embankment constructed in the 1970s.