Niilo Siren is a professional footballer from FIN and is currently 17 years old. He is on the books of Klubi 04 Helsinki and wears shirt number 49. His main role on the pitch is Forward. His stronger foot is Right. His estimated market valuation currently stands at 25K €.

His latest transfer saw him join Klubi 04 Helsinki from Vantaa via on 2026-01-18.

During the Finland Ykkosliigacup 2026 campaign, Niilo Siren made 4 appearances, scoring 1 goals and adding 0 assists. He averaged 0.3 goals per match from 0 shots, with 0 on target.