Phillip Island Road (and its northern section as Thompson Avenue) is a tourist road in Victoria, Australia, serving as the main gateway to Phillip Island, in southern Westernport Bay.

[3] Phillip Island Road commences at the intersection of The Esplanade in Cowes, on the northern coast of the island, and runs south as a two-lane, single carriageway road as Thompson Avenue as the town's main street, before reaching a roundabout with Ventor and Coews-Rhyll Road shortly afterwards, changes name to Phillip Island Road and continues in a south-easterly direction, passing a turn-off to Cape Woolamai, to the easternmost point of the island at Newhaven.

Philip Island Road was signed as State Route 186 between Cowes and Anderson in 1986.

With Victoria's conversion to the newer alphanumeric system in the late 1990s, this was replaced by route B420.

[3] Philip Island Road is entirely contained within the Bass Coast Shire local government area.