As southwestern Florida cruising veterans will tell you, there is an UNOFFICIAL waterway which runs behind Marco Island, and eventually, all the way north to Gordon Pass and Naples. The “unofficial” part means that this passage is NOT part of the Western Florida ICW and is therefore not maintained by the US Army Corps of Engineers.
The shallowest spot on this unofficial Waterway lies near its southern terminus, hard by the southern tip of Marco Island, which is occupied by the fast developing (but still interesting) village of Goodland. Here, you can easily encounter 4 1/2 foot soundings right in the middle of the channel at low water.
Also, a bit farther to the north, where the channel passes under the (northern) Marco Island Bridge, there is an UNBELIEVABLE “L” turn in the channel, just southeast of the span. You MUST pass marker #26 to its eastern and southern sides, or your vessel’s keel WILL find the bottom!!!!!
The southernmost point of this “unofficial Waterway” is known as Coon Key Pass. Cruising craft must traverse the “shallow spot” near Goodland, and then cruise through Coon Key Pass, if they are southbound to Everglades City, Little Shark River or the Florida Keys via this “unofficial waterway route.” Of course, you can avoid all of this by staying offshore, being sure to stay well clear the vast Cape Romano Shoals, and then continuing south.
The messages below pertain to cruising south from Marco Island/Goodland, via Coon Key Pass.

What is the water depth? It looks very shallow. We are heading to Marco on Wednesday and could go to Goodland on our way to Everglades City…IF there is water!
Thanks.
Mike
One September

We’ve been thru Marco to Goodland several times in our boat which drafts 4 ft and haven’t had a problem. The most challenging spots were just after leaving the Marco Bridge (toward Goodland) and when exiting from Goodland back to the Gulf at Coon Key. Pay attention to the tides and charts and it shouldn’t be a problem. It’s our preferred route to avoid Cape Romano Shoals.
Steve and Gina Smith
M/V Island Time

We draw 42″. Go at high tide, or close to it. It’s a soft bottom.
Swing Set

The moon is full, now. Even though the tidal amplitude isn’t much we discovered that inches count!. After poking around south of Cape Romano we decided that the charts were not accurate enough to go into some of the places that warn of 4 feet or less at MLW. Consequently, we headed directly to Marathon because we were in the area at full moon tide and the tide cycle was wrong for us to make a daylight entry into some of the places south of Goodland. We went into Goodland in a friend’s outboard runabout below half tide. At one point the channel was narrow and too shallow to get Sequel in and out, safely. We opted for the Little Marco River and Capri Pass and, at that, there is an uncharted bar on the right of the pass entering the Little Marco where an island blew away in the last hurricane.
Joe aboard M/V Sequel

Two great anchorages on the way to Marathon are Russel Pass outside of Everglades City and Little Shark River. We found them to be one of the nicest anchorages to be at for an overnight stop.
Michael Rizzo

Have made the run from marco to everglades city outside many times, in both bad and good weather. if you trust your gps and the depth sounder you can pick your way through the shoals with no problem, once you have done it its a piece a cake. I draw 5.5 feet.
Nick Chavasse

Don’t forget about the 55′ bridge from Marco to Goodland.
Nick

Click Here To Open A Chart View Window, Zoomed To the Location of Goodland and Coon Key Pass