Mount Gambier is a compact city and most of the main attractions are reachable on foot or by bicycle from the city centre. The Cave Garden is right on the main shopping strip, and the Blue Lake is about a 15-minute walk south from the centre. Valley Lake is adjacent to the Blue Lake precinct and the two can be done as a single loop.
A car is useful if you want to explore the broader Limestone Coast wine region, visit the airport, or get to some of the more outlying cave systems. Most accommodation in the centre of town offers off-street parking.
There is a local bus service, but frequency is limited and it is not well suited for tourist travel between attractions. Taxis and rideshare services operate in the city. Cycling is a pleasant option for getting between the cave and lake sites — the terrain is gently undulating and the distances are short.