Make some phone calls and get some information about potential dives sites before you come and visit. There are a few local businesses and individuals that have good information includingShoreline Charters andLakeshore Adventures in Baileys Harbor. Lakeshore Adventures also has guided trips to area wrecks.
Bring the right gear! Although Lake Michigan looks like an ocean, it isn’t the Caribbean! The water is cold, even during the warmest summer months. A thick, 7mm+ wetsuit or dry suit will be needed to keep you warm.
If you have a boat, bring it along. Although there are some good shore dives in the area, many of the sites, especially the shipwrecks, can only be accessed with a boat.
Use the mooring buoys and be careful if you need to anchor. Many of the wrecks in the area are a hundred plus years old! Careless anchoring can do irreversible damage.
Like almost all dive site today, take only pictures and memories with you as you leave. Almost all of the wrecks along the Door Peninsula are protected pieces of history. Taking anything from them could get you some pretty impressive fines.