Sport is more than just a game—it's a global phenomenon that shapes cultures, economies, and communities. Football, the world's most popular sport, is a prime example. Yet beneath the surface lies an overlooked environmental cost. As the climate crisis accelerates, the sprawling network of football facilities—stadiums, training grounds, and infrastructure—emerges as a silent contributor to environmental degradation and the transgression of planetary boundaries. Two common types of fields exist: artificial and natural turf. Research on environmental impacts of these turfs remains limited, especially in cold climates. This study presents a life cycle assessment of 1 m2 artificial and natural football turfs in Nordic climates, evaluating their environmental impacts such as global warming potential, eutrophication potential and ecotoxicity potential across construction, use, maintenance, and end-of-life phases over operational lifespans of 10, 20 and 30 years. Natural turf exhibited the highest overall environmental impacts over the operational lifespan, e.g. the global warming potential was 30.6 kg CO2 eq/m2 while the artificial turf reached 15.6 kg CO2 eq/m2. During the construction phase, artificial turf generated significant emissions, mainly from material production. In the use phase, natural turf showed the greatest impacts due to diesel consumption and fertilizer application. At the end-of-life stage, artificial turf's sand and infill were reused, while the turf carpet and shock pad were incinerated for energy recovery. However, without recycling, artificial turf would represent the highest environmental burden among the evaluated alternatives. Implementing effective recycling and energy recovery strategies is essential to mitigate its environmental impact. Furthermore, sourcing turf materials locally, combined with substituting conventional maintenance equipment with electric robotic alternatives, can further reduce overall environmental impacts.