Mevagissey and St Austell Bay is an electoral division of Cornwall in the United Kingdom which returns one member to sit on Cornwall Council. It was created at the 2021 local elections, being formed from parts of the former divisions of Mevagissey and St Austell Bay. The current councillor is James Mustoe, a Conservative.
The current division covers the parishes of Carlyon, St Austell Bay and Mevagissey as well as part of the Pentewan Valley parish. It includes the villages of Carlyon Bay, Charlestown, Pentewan, Portmellon and Mevagissey and the hamlets of Tregrehan Mills, Lower Porthpean, Higher Porthpean, Trenarren. The division also includes the Duporth site.