From Toulon : it is possible but a bit complicated to use public transportation (see https://www.reseaumistral.com/). Taking a cab is faster but quite expensive.
From Marseille : take the train to Hyères, then the bus 67 to the Tour Fondue (see https://www.reseaumistral.com/) or a cab.
Fly to Toulon/Hyères, then take a cab. The distance between the airport and the pier is only 8 kms (doable on foot, but not very nice).