Thalassitis joined Conference South side Boreham Wood on a one-month loan deal in October 2011. He made his debut for the club a day after signing, scoring after 17 minutes in a 3–1 home victory against Dartford. During his initial one-month loan spell, Thalassitis made five league appearances for the club, in which Boreham Wood recorded five straight victories — propelling them from twentieth place to eighth in the Conference South standings. His loan spell was subsequently extended for a further month on 9 November 2011. Three days later, on 12 November, Thalassitis scored a hat-trick in Boreham Wood's sixth consecutive league victory, a 4–2 home win against Dover Athletic. After scoring five times in twelve games for Boreham Wood, Thalassitis returned to his parent club on 4 January 2012. He was loaned out for a second time during the season, joining Conference National side Hayes & Yeading United on a one-month loan deal on 17 February 2012. He made his debut for the club a day later, scoring a consolation goal in injury-time in a 4–1 defeat to promotion chasing Wrexham. Thalassitis scored the only goal of the game in his next match three days later, netting with a header from goalkeeper Steve Arnold's long clearance in a 1–0 away victory at Bath City. He scored once more during his time at Hayes & Yeading, scoring in a 3–1 away win at Forest Green Rovers, and played five games during his one-month loan spell. He was recalled by Stevenage on 22 March, and went on to make two further substitute appearances for the club during the latter stages of the season.