The class was considered to be a successful design, and all boats saw extensive active service during World War I, undertaking a range of tasks, including escort duties, shore bombardments, and minesweeping.

All the boats were transferred to the Allies and scrapped at the end of the war, except for four that were allocated to the navy of the newly created Kingdom of Serbs, Croats and Slovenes.

All boats used a single four-cylinder vertical triple expansion engine driving one propeller shaft using steam generated by two coal-fired Yarrow boilers.

[12] The French submarine Cugnot slipped between the protective minefields outside the Bocche di Cattaro and entered the bay on 29 November, but she was spotted by 57 T, commanded by Linienschiffsleutnant Albert Heinz-Erian, who raised the alarm.

[14] On 20 December, the French submarine Curie posed a serious threat when she entered the harbour at Pola and became tangled in anti-submarine net cables.

[15] On 14 February 1915, 68 F, the Huszár-class destroyer Csikos and the Cobra-class torpedo boat SMS 15 bombarded Dulcigno and Antivari on the Montenegrin coastline, and searched for the Montenegrin royal yacht Rumija which was being employed towing lighters with supplies from Medova in Albania to Antivari and into the Bojana estuary.

[12] The constant Austro-Hungarian attacks, combined with the expectation that Italy would soon enter the war on the Allied side, meant that the French abandoned their efforts to supply Antivari by sea.

[18] As expected, Italy declared war on Austria-Hungary on the afternoon of 23 May, and almost the entire Austro-Hungarian fleet left Pola soon after to deliver an immediate response against Italian cities and towns along the Adriatic coast, aiming to interdict land and sea transport between southern Italy and the northern regions of that country which were expected to be a theatre of land operations.

[20] Group C, consisting of the pre-dreadnought Radetzky escorted by 56 T and 73 F, bombarded Potenza Picena, Termoli and Campomarino, damaging some bridges.

[22] The Italian submarine Velella and 65 T engaged in a torpedo duel outside the entrance to Cattero Bay on 17 August, but neither vessel was damaged.

[26] A seaplane attack on Ancona on 9 December was supported by 57T and 58T, accompanying the protected cruiser Szigetvár, two destroyers and three 250t-class torpedo boats.

[27] On New Year's Day 1916, the Austro-Hungarians began preparations for an assault on the Lovćen mountain range – located in the hinterland south of the Bocche – supported by both land and naval bombardments.

[31][32] The damaged 65 F was towed to Pola for repairs, and the loss of Balilla resulted in the Italians withdrawing submarine patrols closer to the Otranto Barrage.

[31] On 1 August, a large Italian air raid on Fiume was intercepted by Austro-Hungarian aircraft, including one flown by the flying ace Gottfried Freiherr von Banfield, and he drove off three bombers and forced another down.

The downed aircraft was towed to Pola by 69 F.[33] On 7 October, 68 F was transporting supplies to the seaplane station at Durazzo when she encountered four Indomito-class destroyers, with another four apparently also in the area.

[34] On the following day, the same boat encountered the Italian Rosolino Pilo-class destroyer Pilade Bronzetti off San Giovanni di Medua, but after a brief chase was able to reach the cover of a shore battery.

[1] On 16 November 1917, 61 and 65 were part of a minesweeping force supporting the bombardment of a 152 mm (6.0 in) Italian shore battery at Cortellazzo near the mouth of the Piave.

[37] All boats were due to have their aft torpedo tube replaced by a single Škoda 66 mm (2.6 in) L/30 anti-aircraft gun in late 1918, but it is not clear whether this actually occurred.

[4][38] Following World War I, the Kaiman-class boats were allocated to Great Britain, Italy and the new Kingdom of Serbs, Croats and Slovenes, which was later renamed Yugoslavia.