Red-filled: nations that have hosted a pro–am tournament but are yet to host a fully professional tournament.
This is a list of professional and alternative format snooker tournaments. Professional snooker tournaments can take the form of ranking tournaments—which are open to players on the main tour and award ranking points based on a player's performance—and non-ranking tournaments. A non-ranking tournament may take the form of an invitational event where player participation is conditional on criteria set by the organiser or sponsor or by personal invite. Most tournaments take the form of a 'singles' event, but there are several team formats that have appeared on the calendar over the years.
In recent seasons alternative forms of snooker have proliferated on the calendar. Any event that uses the official rules of snooker but is not completely consistent with them is defined as an "alternative form of snooker", such as six-red snooker (which is played with six reds as opposed to the standard fifteen as required by the official rules), and alterations to scoring and fouling. Some tournaments have occupied the middle ground between strict adherence to the official rules and adopting an alternative format by implementing tournament rules that fully complement the official rules of the game, such as adding a shot clock or call shot; in such instances, a tournament rule operates in a way that the official rules of the game are still fully observed.