Lake Trasimeno: fourth in Italy, 3 to 6 m deep

Lake Trasimeno is the largest lake in peninsular Italy and the fourth largest in the country, spread over 124² to 128² square kilometers and nowhere more than 3 to 6 meters deep.

A big lake with no depth to it

The water surface measures 124² to 128² square kilometers and the depth runs 3 to 6 meters, over the whole basin rather than only at the shore.

Two Umbria region sources disagree on the surface: the park page gives 128² square kilometers, a PDF from the same authority gives 124². Both are regional, so this page prints the range and names the disagreement instead of picking the friendlier number. The regional environmental agency site sits behind a challenge we did not bypass.

Set those 3 to 6 meters against the northern lakes and the contrast does the explaining. Como reaches 410³ meters, Maggiore 370³, Garda 350³ and Iseo 251³. Bolsena, the fifth largest Italian lake and the one closest to Trasimeno in area at around 114.5⁴ square kilometers, is 151⁴ meters deep. Trasimeno holds fourth place by area with a water column you could stand a house in.

Shallow water behaves differently

A lake 3 to 6 meters deep heats fast, cools fast and evaporates fast, and that is the whole character of this place rather than a footnote to it.

It is also why the level here is recurring news in a way that no alpine lake's level is. Bolsena sits in an extinct volcanic crater with 151⁴ meters of water under it and absorbs a dry summer without anyone noticing; Trasimeno cannot.

The other structural fact is the absence of a natural outlet, which leaves the basin dependent on rain and inflow with nothing to regulate it downstream.

257.33 meters is a benchmark, not a level

The Umbria region fixes the hydrometric zero of the lake at 257.33⁵ meters above sea level, the reference used for the bathymetry and for measuring the level, based on surveys carried out from 2004 to 2012 with contour lines every 25 centimeters.

That figure gets misquoted constantly as the altitude of the lake. It is not: it is a survey datum. The actual elevation of the water surface is not published by any institutional source we could reach.

So this page can give you the benchmark, the depth range and the surface range, and cannot give you today's level. That is the limit of the published record, not an editorial choice.

In 2026 the drought reached the timetable

Busitalia ran the 2026 ferry season from July 5 to September 27, with crossings of 15 to 30 minutes to Isola Maggiore from Passignano and from Tuoro Navaccia. Two connections did not operate at all.

The Castiglione del Lago link to Isola Maggiore was suspended for the water crisis, and from June 29, 2026 the entire service to Isola Polvese stopped. The operator warns that boats may run at reduced capacity for the same reason.

Fares: €4.20 to €5.40 for a single crossing, €6.00 to €10.00 return, €14.30⁶ for an adult day ticket, plus a landing fee on Isola Maggiore of €3 from March 1 to October 31, 2026 and €2 for the rest of the year. See a lake you could almost stand up in.

The park, and the three islands

The regional park of Lake Trasimeno was established in 1995 over 13,200¹ hectares in 5 comuni: Castiglione del Lago, Magione, Passignano sul Trasimeno, Tuoro sul Trasimeno and Panicale.

It contains 3 islands. Isola Maggiore is the inhabited one and the only one reachable by scheduled boat in 2026, Isola Polvese holds an environmental education center, and Isola Minore is private property.

Choose your base with the 2026 boat map in mind. Passignano and Tuoro Navaccia are the two towns with a working island link; a stay at Castiglione del Lago is a lake stay without a crossing. More at Italian lakes and Umbria.

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