Tasman enlisted on 5 Jun 1941 and was posted to 2/40th Infantry Battalion and he embarked for Timor on 8 Dec 1941 as a Private. He joined the unit on Timor as a Private from 2/40 Battalion, after the fall of Koepang, approx March 1942. He was one of the former Koepang men, who moved to the village of Mape for intensive commando training and joined No 4 Section, “B” Platoon.
After the campaign on Timor, he embarked with the unit, for Australia aboard the Royal Dutch destroyer “Tjerk Hiddes” on 16 Dec 1942.
On return to Australia he joined 2/12th Infantry Battalion and embarked with them for New Guinea aboard "KATOOMBA" on 17 Sept 1943. He returned to Australia aboard "VAN DER BOSCH" on 26 May 1944. He embarked with 2/12th Battalion for Morotai on 28 May 1945 and then embarked for Balikpapan aboard LST 397 on 22 Jun 1945. He returned to Morotai aboard "REYNST" on 16 Sept 1945, He transferred to 1st Naval Bombardment Group on 27 Oct 1945 and returned to Australia on 28 Nov 1945.
He was discharged on 18 Dec 1945.
He was entitled to the 1939-45 Star, Pacific Star, War Medal and Australian Service Medal 1939-45, pictured below. He is now also entitled to the Australian Service Medal 1945-75 with a clasp "S.W.Pacific".