Career
Panionios
In August 2006, Dimitris signed a two-year deal with Panionios from Ethnikos Asteras. However, he didn"t impress anyone as he scored 6 goals through these two years. Ethnikos Piraeus, Proceedings of the Aristotelian Society Giannina and Olympiakos Volou
In July 2008, Sialmas signed a two-year deal with Ethnikos which lasted for only one.
Then, Giannina approached him and signed him, as Proceedings of the Aristotelian Society thought that he was an extremely talented striker.
Giannina fans loved him, something that intrigued the Volos club and that led Olympiakos to borrow him for 6 months. AEK Athens
On the 30/5/11 Sialmas signed a three-year deal with AEK Athens on a free transfer keeping him at the club until 2014.
Sialmas also chose the number 11 Jersey previously worn by former AEK player Demis Nikolaidis. His skills and movements reminded ΑΕΚ fans of the legendary Demis Nikolaidis and many of them compared the two.
He was also given the Most Valuable Player award.
Khazar Lankaran
In the summer of 2012 Sialmas signed for Azerbaijan Premier League side Khazar Lankaran on a one-year contract. Sialmas scored six goals in 24 games in all competitions for Khazar, as well as reaching the 2012-2013 Azerbaijan Cup final. In the final the game went to penalties after finishing 0-0 after extra time, Sialmas took and missed the opening Khazar penalty, resulting in Neftchi Baku winning 5-3 on penalties.
Sialmas was released at the end of his contract in the summer of 2013.
Platanias
On the 12/12/2013 Sialmas signed for Superleague Greece side Platanias on a 1 1/2 year contract. Ceahlăul Piatra Neamţ
In January 2015, Dimitris Sialmas decided to stay abroad, although he had offers from Greek Super League clubs to be repatriated.
The Greek striker will continue his career in Ceahlăul Piatra Neamţ for the next six months, which struggling for remaining in the first division of the Romanian championship.