The Sun Odyssey 28.5 is a French sailboat that was designed by Tony Castro as a cruiser and first built in 1994.
The design was originally sold as the Sun Way 29.
The design was built by Jeanneau in France, starting in 1994, but it is now out of production.
The Sun Odyssey 28.1 is a recreational keelboat, built predominantly of fiberglass, with wood trim. It has a fractional sloop rig, a raked stem, a reverse transom with steps, an internally mounted spade-type rudder controlled by a tiller and a fixed fin keel or optional keel and centerboard. It displaces and carries of ballast.
The boat has a draft of with the standard fin keel fitted.
The boat is fitted with a Japanese Yanmar diesel engine of for docking and maneuvering. The fuel tank holds and the fresh water tank has a capacity of .
The design has sleeping accommodation for four to six people, with a double "V"-berth in the bow cabin, two straight settees in the main cabin and an aft cabin with a double berth on the port side. The galley is located on the port side at the companionway ladder. The galley is L-shaped and is equipped with a two-burner stove, an ice box and a sink. A navigation station is opposite the galley, on the starboard side. The head is located aft, opposite the galley, also on the starboard side.
The design has a hull speed of .
In a 1995 Cruising World review, Quentin Warren described the design as, "a high-volume mini-cruiser designed by Tony Castro ... and another in the French mega-builder's line of finely turned out family oriented sailing vessels."