Rome doesn't have the deep, decades-old multisport infrastructure of a city built around triathlon — but it has something arguably more interesting for a guide like this: two specific, real venues with genuine racing history, and a claim to being where the whole sport in this country started.
Where Italian triathlon actually began
Triathlon in Italy traces back to a first competition held on the beach at Ostia — Rome's own stretch of coast — in 1984. The Federazione Italiana Triathlon (FITri), the national governing body, was formally recognised as a national sports federation in December 2000 and is headquartered at the Stadio Olimpico in Rome. Roma Triathlon is the FITri-affiliated local club for anyone wanting to train or race with an established Roman group rather than going it alone.
The Laghetto dell'EUR — Rome's real triathlon lake
The Laghetto dell'EUR (EUR Lake), an artificial lake in the EUR district a few kilometres south of the Colosseum, is the closest thing Rome has to a dedicated triathlon swim venue, and it has real racing history rather than speculative potential. Challenge Roma 753 — an annual long-course triathlon that's used the lake as its swim venue since launching in 2017 — takes its name and its distinctive distances from Rome's founding year, 753 BC: a 1.753km swim in the Laghetto, a 75.3km bike leg heading out towards Ostia before returning to the city centre, and a 17.53km run. World Triathlon Cup Rome, a sprint-distance race (750m swim/20km bike/5km run), also used the same lake for its swim leg in 2023 and 2024, with the bike course passing the Palazzo della Civiltà Italiana and the run through Central Park EUR — a district built for the 1960 Rome Olympics.
Raced in, not yet open for a swim
Don't confuse "the Laghetto has hosted competitive swims since 2017" with "you can swim there any day you like." Those races use the lake roped off for a single event day each year, run by the organiser under permit — it isn't a public open-water swimming spot. A separate city project has targeted making the lake permanently, publicly swimmable by the end of 2027, but that's a distinct, not-yet-completed goal, not the current state of things.
Ostia — the coast with a world championship pedigree
Ostia, roughly 25-30km southwest of the city centre, is Rome's genuine open-water venue, with a track record well beyond local racing: it hosted the open-water swimming events (5km, 10km and 25km) at both the 2009 World Aquatics Championships and the 2022 European Aquatics Championships. FITri also runs its Roma Open Water event from the Porto Turistico di Roma, the marina at Ostia. Widely published sea-temperature averages put the water at roughly 26°C through July and August, with the general swimming season (staying above 20°C) running June to October — warm enough that a wetsuit is likely to sit in optional-to-not-permitted territory under a standard World Triathlon-style temperature threshold for most of that window, though the specific rule for any given event should always be checked directly rather than assumed from a seasonal average.
T100 Rome — new, and still mostly unconfirmed
T100 Rome is set for 5-6 June 2027, part of the newly unified Triathlon World Tour launched by the PTO and World Triathlon in July 2026 — a genuinely new venue for the series rather than an established race gaining a new sponsor. Verus's dedicated race guide covers what's known in full detail; the short version here is that Rome's elite race sits on the shorter T50 World Championship Tour rather than the 100km T100 tour, and the organiser's own site still lists the accompanying age-group distances as "TBC." Neither the Laghetto dell'EUR nor Ostia has been confirmed as the swim venue — both are plausible given Rome's real precedent covered above, but neither is fact yet.
Official sources
Training for a Rome-area swim
Whether you end up racing Challenge Roma 753, a FITri open-water event at Ostia, or a future T100 Rome, the preparation is the same: know your pace in open water, not just a pool, and have a realistic split plan going in rather than hoping the numbers work out on the day.