Photo: Julian Lupyan, CC0 Free parks & gardens in Brussels
Photo: Julian Lupyan, CC0 
Photo: Diego Delso, CC BY-SA 4.0 Parc du Cinquantenaire
Free outside, paid inside
Photo: No machine-readable author provided. Ben2~commonswiki assumed (based on copyright claims)., CC BY-SA 3.0 Brussels Park
Free, always
Photo: GdML, CC BY-SA 3.0 Bois de la Cambre
Free, always
Photo: Trougnouf (Benoit Brummer), CC BY 4.0 Parc Josaphat
Free, always
Photo: Schölla Schwarz, CC BY 3.0 Leopold Park
Free, always
Photo: Trougnouf (Benoit Brummer), CC BY 4.0 Botanical Garden of Brussels
Free, always
Photo: Jopparn, CC BY-SA 3.0