Apart from some 19th century leftovers, the Austro-Hungarian fleet operated a total of 63 modern torpedo boats during the First World War.
The initial class was the 24-strong Kaiman-Class. The type boat was ordered from Yarrow on 1904 and delivered in 1905; it was used as a template for 23 identical copies, 13 by STT/Trieste and 10 by Danubius/Fiume. Displacing 210 tons, they were oceangoing and capable of 26 knots; they carried four 47mm Skoda guns (two on each broadside) and three 450mm torpedo tubes (two abreast behind the bridge, one on the centerline aft). They initially received names, but were redesignated with numbers (including a suffix indicating the building location) in 1913. E meant 'England', T meant 'Trieste' and F 'Fiume'. In sequence, the boats were: Kaiman / 50E, Anaconda / 51T, Alligator / 52T, Krokodil / 53T, Wal / 54T, Seehund / 55T, Delphin / 56T, Narwal / 57T, Hai / 58T, Möwe / 59T, Schwalbe /60T, Pinguin / 61T, Drache / 62T, Greif / 63T, Triton / 64F, Hydra / 65F, Skorpion / 66F, Phönix / 67F, Krake / 68F, Polyp / 69F, Echse / 70F, Molch / 71F, Kormoran / 72F, Alk / 73F.
During the war, they were retrofitted with w/t; other modifications are not recorded (as far as I know). From 1917, the builders designator was dropped from their pennants, leaving just the number.
All survived the war; four were ceded to Yugoslavia and commissioned as T9 through T12 (phased out in 1929/30), the others scrapped by the UK in Italy.
While the Kaimans were under construction, a class of first-class torpedo boats half their size were ordered to an entirely domestic design. As usual in the KuK empire, parliamentary approval could not be gained unless half the 12-ship class was built on the Hungarian Danubius yard. These single-screw boats were a successful design; they were fast, handy and seaworthy, being good for 28 knots, although the Hungarian ones listed badly when going at full tilt. Two 47mm guns and two 450mm torpedo tubes were arranged on the centerline, giving the same broadside as the much larger Kaimans. They did not get names, but latin numbers from I to XII.
The only difference between both groups was the location of the searchlight, which was in front of the funnel on STT units and on the bridge on Danubius boats. Completed in 1909/11 without w/t, all were retrofitted during the war.
Eleven of twelve units were ceded to Italy after the war; the twelfth boat already defected to the Italians before the war was over after a mutiny. Two served till 1925 before they were scrapped, the rest was scrapped forthwith.
After the Kaiman-class production run was complete, a follow-on class of oceangoing torpedo boats was designed, to be even larger, faster and more seagoing than the already successful Kaimans. These craft also were successful and popular; they could steam at 28 knots and toted two 66mm guns and four 450mm torpedo tubes on the centerline. Size- and performance-wise, they were best compared to the later German A II / III type. A total of 27 were built (eight at STT / Trieste (pennant suffix T) three at CNT / Monfalcone (pennant suffix M) and sixteen at Danubius / Fiume (pennant suffix F). The first units were commissioned in 1913, after the Kaimans had shed their names, and never received names of their own. The STT-built boats 74T through 81T were the shortest of them all and the only ones with a single funnel.
The Danubius-built boats 82F through 97F had two funnels, lower bridges and a straight stem.
The last three 98M through 100M (completed earlier than the lower numbered Danubius craft) were the most seaworthy of the lot, with the forward torpedo tubes on forecastle deck level.
At least one of them had a different mast arrangement, probably retrofitted; I've not found any pictures showing this modification on any of the STT and Danubius boats.
None of these units were lost during the war, indicating few operational sorties. Of the STT-batch, four were ceded to Yugoslavia after the war (becoming T1 through T4, and four to Rumania, becoming Viforul, Vartej, Vijelia and Zborul. The first three Rumanian units were phased out in 1927, and two of the Yugoslav boats during the 1930s. The three surviving boats saw active service in WWII, the Yugoslav ones with three different operators (they were first captured by Italy, then by Germany). The Danubius-batch was divided between Rumania (Naluca, Zmeul, Fulgerul), Portugal (Zezere, Ave, Cavado, Sado, Liz, Mondego), Greece (Panormos, Proussa, Pergamos) and Yugoslavia (T5 through T8). Many were phased out and scrapped between the wars, but two Rumanian, two Greek and all Yugoslav boats saw active service in World War II. Only one Rumanian and one Yugoslav boat survived the war, both scrapped in the 1950s. The last three were ceded to Greece, becoming Kyzikos, Kios and Kidoniai; all were destroyed in World War II.