For a long, open, and pleasant waterfront run, it’s possible to run for 6.4 km between Roquebrune-Cap-Martin and Menton. It’s a mix of dedicated waterfront promenade and wide, palm-lined sidewalk along the D52 road (which changes names multiple times). There are excellent beach and sea views for much of the way. There are a few spots where the path is a bit away from the water or there are buildings blocking the view, but it’s ~75% ocean views over the course of the trail. Pro Tip: can do one-way and return via train/bus! 

Google Street View

The west end start is in Roquebrune-Cap-Martin, and is a continuation of the Cap Martin route. Follow the promenade/sidewalk along the Baie de Soleil east toward Menton, enjoying the views.

At 3 km you’re in Menton, where there’s another scenic 3 km that combines a jaunt out to the lighthouse (Phare de Menton), and then around the marina/port to a couple of viewpoints, and then along the Plage des Sablettes (beach) and another quai to Av. Aristide Briand. There are great views of fancy boats, and a people scene at the beach. 

Add-Ons: The Sentier du Corbusier path around Cap Martin adds up to another 4 km west toward Monaco.