Agility is a skill used to give you access to certain shortcuts within dungeons and special locations.
Requirements - NONE
Levels 1-35; Gnome Agility Course
Levels 35-52 | Barbarian Outpost Agility Course
Levels 52-77/85 | Wilderness Agility Course
Levels 85-90 | ADVANCED Gnome Agility Course
Levels 90-99 | ADVANCED Barbarian Agility Course
NOTE: Other option to train agility, which is also the best is at Prifddinas, which gives a really good xp amount but click intensive.
To access prifddinas, you either need the perk to access instantly or 1900 total level.