Grand Prix CusioCup

Lake Orta is widely celebrated as the cleanest lake in Europe, drawing open water swimmers with its remarkably clear and crystalline waters. Staged in June by organizer CusioCup, the Grand Prix CusioCup is an open water swimming race held in the freshwater basin of Lake Orta at Pettenasco in the Piedmont region of northern Italy. Swimmers gather at the municipal beach by Bar Dolphins to plunge into water. The event lays out a multi-distance program that accommodates both endurance veterans and sprint specialists across calibrated circuits. The morning schedule opens with the long-distance challenges, launching the 6-kilometer marathon across four laps of a 1.5-kilometer course, closely followed by the 3-kilometer competition covering two laps of the identical loop.

Around midday, the competition turns to shorter efforts with a 1.5-kilometer race contested over two 750-meter laps. In the afternoon, excitement peaks with the team relay, where trios cover three 750-meter legs for a combined distance of 2.25 kilometers. Rigorous safety standards and straightforward gear regulations shape the experience on the water. While wetsuits are officially recommended across all distances to maintain thermal comfort, the use of propulsion aids such as fins and hand paddles is strictly forbidden. For the 1.5-kilometer distance, participation is open to swimmers from eleven years of age with parental authorization, provided they submit a non-competitive medical certificate.

Lake Orta: glacial deeps and the north-flowing Nigoglia

Lake Orta owes its basin to deep geological time, carved out by the advancing southern front of the ancient Simplon glacier. This glacial scouring left behind a protected alpine depression that boasts some of the clearest freshwater in Europe. Beneath the surface, the lake bed is split into two distinct sub-basins by a submerged rock ridge lying roughly 100 meters deep between Punta Crabbia and the village of Ronco. North of this underwater divide, the northern basin plunges steeply to reach the lake's maximum depth of 143 meters. Under one kilometre from the event grounds, the Scarpia stream flows down from its source in Madonna del Sasso at 400 meters above sea level.

About two kilometres from the race area, the Plesna torrent begins northeast of Monte Avigno and discharges into Lake Orta just south of the town center of Pella. In the same area about two kilometres from the venue, the Pellino stream flows down from an altitude of approximately 900 meters between the Cusio basin and the lower Val Sesia. Carving deep gorges of exceptional natural interest, the Pellino supports wild populations of brown trout, rainbow trout, and common minnow, protected as a dedicated FIPSAS fishing reserve requiring a special license. Unlike almost every other subalpine body of water, Orta displays an astonishing hydrographic quirk at its northern tip. While major pre-alpine lakes drain southward into the Po Valley, Lake Orta's only emissary, the Nigoglia, heads north toward the high Alps. Flowing out from the lake, the river runs for less than two kilometers through the center of Omegna before merging with the Strona torrent. In the elevated terrain surrounding the basin, smaller natural water features punctuate the landscape.

Isola di San Giulio: Neolithic traces and royal sieges

Resting approximately 400 meters from the shore, Isola di San Giulio forms the geographic and historic focal point of the lake. The compact island measures 275 meters in length and 140 meters in width, bounded by a perimeter of about 650 meters. Archaeological excavations have unearthed ceramic fragments confirming human settlement here dating back to the Neolithic era, with evidence of continuous habitation through the Iron Age. During late antiquity, the island was fortified between the 5th and 6th centuries as a bulwark against invaders descending from the Simplon Pass. In 590, the Lombard Duke Mimulfo was beheaded here for treason under orders from King Agilulfo. In 962, Queen Willa, wife of King Berengar II, reinforced the defenses with the Queen's Wall to withstand an imperial siege. Her forces resisted for two months before surrendering to Otto I of Saxony. The medieval fortress castle stood until 1841, when it was demolished to build the grand Bishop's Seminary that commands the island today.

Pettenasco waterfront: piers, sandy bays, and lakeside villas

The eastern shore at Pettenasco provides an ideal setting for swimmers transitioning from the water to post-race recovery. Dolphin's beach combines natural lake frontage with full hospitality, offering a convenient bar, restaurant, changing showers, and restrooms right beside the swimming zone. After logging their laps, athletes and supporters can stretch out across fine sand, with loungers and parasols available along the water's edge. The town's shoreline promenade extends along manicured grassy patches and stretches of fine sand, accented by modern open-air sculptures and wooden piers jutting into the crystalline shallows. A stone stairway climbs up to an intimate path shaded by an overhead pergola, curling behind historical lakeside villas and private boat shelters that look directly out onto the water. Standing on the sun-warmed wooden jetties, looking across the tranquil ripples of the bay, swimmers can fully appreciate the calm, transparent water that makes this alpine lake such a rewarding destination to swim.