The name is documented in 827 as in vico Duplago, in a charter of the bishopric of Freising, later germanised into Douplach in 993 and Toblach in 1020. One of the proposed readings takes it as Duplagum, two waters, and the geography agrees: nearby there are two lakes and two important rivers rise. The Drava springs a little to the east of the village and ends in the Danube; the Rienza is born under the Tre Cime and heads for the Adriatic. The Alpine watershed passes through the municipality, and Toblach is the piece of Italy whose water reaches the Black Sea.
In the summers between 1908 and 1910 Gustav Mahler worked here, in a small wooden hut in the middle of the woods: there he composed the Ninth Symphony, the last he managed to finish, and Das Lied von der Erde, and there he began the Tenth. Much further back, a milestone dedicated to the emperor Gordian the Third, found at the Gratsch bridge, proves that the Roman road of the Puster valley passed this way. The village, finally, is divided in two: Old Toblach, higher up, and New Toblach, built at the beginning of the twentieth century beside the railway station, exactly astride the saddle.