Though nearly obsolete by the beginning of World War II, the T-26 was the most important tank of the Spanish Civil War and played a significant role during the Battle of Lake Khasan in 1938 as well as in the Winter War. The T-26 was the most numerous tank in the Red Army's armoured force during the German invasion of the Soviet Union in June 1941. The Soviet T-26 light tanks last saw combat in August 1945, in Manchuria.

The T-26 was used extensively in the armies of Spain, China and Turkey. In addition, captured T-26 light tanks were used by the Finnish, German, Romanian and Hungarian armies.

Prewar years

The first unit equipped with the T-26 was the 1st Mechanized Brigade named after K.V. Kalinovsky (the Moscow Military District). Tanks delivered to the Red Army through the end of 1931 were unarmed and intended for training, and the T-26 entered active service in 1932 only. The first series-produced T-26 tanks were shown to the public during the military parade on Red Square in Moscow on 7 November 1931—the 14th anniversary of the October Revolution. New mechanized brigades, each equipped with 178 T-26 tanks, were also organized at that time.Svirin, Kolomiets (2000), p. 48 The RKKA Staff decided to form larger tank units based on experience gained in military exercises of 1931–1932: so mechanized corps were created in the Moscow Military District, the Ukrainian Military District and the Leningrad Military District in autumn 1932. Each mechanized corps consisted of two mechanized brigades (one equipped with the T-26 and another with the BT). From 1935, mechanized corps were equipped only with BT tanks.

When series production of the T-26 mod. 1933 started, each tank platoon consisted of three vehicles (one single-turreted mod. 1933 and two twin-turreted mod. 1931 tanks). Later, the majority of twin-turreted T-26 tanks were given to combat training depots and to tank battalions of rifle divisions (in the beginning of 1935 tank battalion of rifle division consisted of 3 companies, 15 T-26 tanks in each).

In August 1938 mechanized corps, brigades and regiments were reorganized into corresponding tank units. In the end of 1938 the Red Army had 17 light tank brigades (267 T-26 tanks in each) and 3 chemical tank brigades (equipped with flame-throwing tanks based on the T-26 chassis).Baryatinsky (2003), p. 44

Spanish Civil War

The Spanish Civil War was the first conflict in which the T-26 participated. At the request of the Spanish Republican government, the Soviet government sold weapons and military equipment to Spain and provided military advisers (including crews) within the framework of Operation X. The first shipment of tanks to Spanish republicans was delivered on 13 October 1936, at the Spanish port city of Cartagena; fifty T-26s with spare parts, ammunition, fuel, and around 80 volunteers under the command of colonel S. Krivoshein, the commander of the 8th Separate Mechanized Brigade. The first German delivery of armoured vehicles to Franco's insurgent Nationalist forces was of Panzer I light tanks for the Condor Legion, which arrived only a week later. The Italians had begun to provide Nationalists with CV-33 tankettes even earlier, in August 1936.

Republican and Nationalist tanks saw their first combat during the advance of Franco's forces towards Madrid, and during the Siege of Madrid, where the Nationalist Panzer I and CV-33 tankettes suffered heavy losses from Republican tanks armed with 45mm guns. The first Soviet T-26 tanks delivered to Cartagena were intended for Republican tank crews training in the Archena training center (90 km from Cartagena), but the situation around Madrid became complicated and fifteen tanks formed a tank company under the command of a Soviet officer, Pols Armans.

Armans' company engaged in battle on 29 October 1936 near Seseña, 30 km south-west of Madrid. Twelve T-26s advanced 35 km during the ten-hour raid and inflicted significant losses to Francoists (around two squadrons of Moroccan cavalry and two infantry battalions were defeated; twelve 75 mm field guns, four CV-33 tankettes and twenty to thirty trucks with cargo were destroyed or damaged) with the loss of 3 T-26 tanks to gasoline bombs and artillery fire. The first known instance of ramming in tank warfare was made that day when the T-26 tank of platoon commander Lt. Semyon Osadchy encountered two Italian CV-33 tankettes from the Nationalist 1st Tank Company near Esquivias village and overturned one of them into a small gorge. Crewmembers of another tankette were killed by tank machine-gun fire after they abandoned their vehicle. The T-26 of Armans was burned by a gasoline bomb; although wounded, Armans continued to lead the tank company. Armans' T-26 destroyed one, and damaged two CV-33 tankettes by tank gun fire. On 31 December 1936 Armans was awarded with the Hero of the Soviet Union for that tank raid and active participation in the defense of Madrid. On 17 November 1936, Armans' company had five T-26 tanks in operable condition.Rybalkin (2000), p. 66Garcia (2006), p. 320Soviet Tank Operations in the Spanish Civil WarBaryatinsky (2006), p. 81

The day before (28 October 1936) Francoist cavalry and Panzer IA tanks from the 88th Tank Battalion met with Republican T-26 tanks. The Pz.IA proved to have insufficient armament when pitted against the T-26.Baryatinsky (2003), pp. 44–45

The Krivoshein's tank group, consisting of 23 T-26 tanks and 9 armoured cars, attacked Francoists on 1 November 1936, supporting the main Republican column retreating to Madrid. The Krivoshein's tank group took part in the fighting for Torrejón de Velasco and Valdemoro on 4–5 November 1936, a counter-attack in the suburb of Cerro de los Ángeles on 13 November 1936, and in continuous fighting inside Madrid itself through the middle of December 1936. Soviet military personnel of Krivoshein's group returned to the USSR in the end of November 1936, except for some tankers from Pogodin's company, mechanics from Alcalá de Henares tank repair base and military instructors from the Archena training center.Kolomiets (2007), p. 124

The 1st Republican Tank Brigade initially consisted of a tank battalion, a Spanish motorcycle company and a transport battalion. It was created in December 1936 on the delivery of about 100 Soviet tanks and military personnel under the command of Soviet brigade commander D. Pavlov at the Archena training center. The Soviet volunteer tank commanders and drivers sent to Spain were from the best tank units of the Red Army: the Mechanized Brigade (named after V. Volodarsky) from Peterhof, the 4th Separate Mechanized Brigade from Babruysk (commander – D. Pavlov), and the 1st Mechanized Corps named after K.B. Kalinovsky from Naro-Fominsk. The tank gunners were usually Spanish.

The 1st Republican Tank Brigade (1.a Brigada Blindada) first saw action near Las Rosas and Majadahonda (north-west of Madrid) in the beginning of January 1937, supporting the 12th and 14th International Brigades. This action broke up the second Nationalist assault on Madrid.

There were around 70 T-26s in the Republican Army in the beginning of 1937. In February 1937, company-sized detachments of the Tank Brigade participated in the Battle of Jarama. On 14 February 1937 the Tank Brigade, together with the 24th Infantry Brigade, took part in a counterattack and overcame a major Nationalist force, causing about 1000 Nationalist casualties. On 27 February 1937, the Tank Brigade launched five attacks on Nationalist positions without infantry support, but took heavy losses from anti-tank guns (35 to 40 percent of its tanks in some attacks). Nevertheless, the T-26 was used with great success during the Battle of Guadalajara in March 1937 after the 1st Tank Brigade was finally formed (its HQ was in Alcalá de Henares). For example, a platoon of two T-26 tanks under the command of Spaniard, E. Ferrera destroyed or damaged twenty-five Italian tankettes on 10 March 1937. In September/October 1937 the Republican 1st Tank Brigade was disbanded. Some volunteers returned to the USSR, while others joined with the International Tank Regiment under the command of Soviet major S.A. Kondratiev.Baryatinsky (2006), p. 82

From autumn 1937, all T-26 tank crews were Spanish. In summer 1938, the Republican Army had two armoured divisions, formed with Soviet help.Baryatinsky (2006), pp. 81–82 Turrets from irreparable T-26 and BT-5 tanks and from BA-6 armoured cars were mounted on Chevrolet 1937s and other armoured cars developed and produced by the Republicans. Republican armour and infantry often suffered from cooperation problems throughout the war. T-26 tanks often attacked enemy trenches or defense positions in the narrow streets of Spanish towns without support, where they met strong resistance. Nationalist infantry, the Moroccans especially, defended courageously despite heavy casualties, throwing hand grenades and gasoline bombs, which are dangerous to tank engines.House, pp. 68–69For a brief summary of anti-tank tactics during the Spanish Civil War see: Weeks, Men Against Tanks

Ultimately, the Soviet Union provided a total of 281 T-26 mod. 1933 tanks, which were used by the Republicans in almost all the battles of the Spanish Civil War. Many sources state that a total of 297 T-26s were delivered to Spain but this probably includes the first planned delivery of 15 T-26s on 26 September 1936.García, p. 320

Approximately 40 percent of T-26s fell into Nationalist hands by the end of the war, mostly after the defeat of the Republicans. In March 1937, a tank company of captured T-26 tanks was included into Panzergruppe Drohne, a tank unit of the German Condor Legion in Spain. The Nationalists prized the Soviet tanks, even offering a bounty of 500 pesetas for each tank captured intact. In August 1937, a reorganization of the Drohne Group into Spanish control started, which resulted in the formation of Bandera de Carros de Combate de la Legion, a part of the Spanish Foreign Legion, in March 1938. The Bandera consisted of two battalions (1. and 2. Agrupaciones de Carros). One was equipped with Panzer I tanks and the second with captured T-26 tanks. Approaching 1939, both battalions had similar organization, their third companies equipped with T-26 tanks. The Nationalists used captured T-26 tanks in the Battle of Teruel, Battle of Brunete, Battle of Bilbao, Battle of the Ebro and the Catalonia Offensive. The Nationalists developed their own light tank prototype (Verdeja) during the war, with the wide use of elements from Panzer I, and especially the T-26. Later, T-26s formed the base of the Spanish Brunete Armoured Division, serving until 1953.Baryatinskiy (2003), p. 62. For more specific information see: García and Franco, Las Armas de la Guerra Civil Española, p. 321.