Where are you flying into ? After you get to Mackinaw city or St. Ignace there are many ferry's to take to the island. I used sheplers had a nice ride under the bridge and then to the island
St. Ignace and Mackinaw City, Michigan has both Sheplers and Starline ferries and offer discounts/tickets for some attractions on the Island. I personally found Starline to be a tad cheaper for what I was looking for when I visited early August 2019. Both ferries offer free lots and secure valet parking if you're worried about a rental car. Starline offers a slow ferry which takes about 30min or a faster boat about 15min. There are a few times were the ferry can detour under the Bridge. Mackinaw City is more touristy, but I found hotel rooms to be a little cheaper in St Ignace if money is a factor.
Well first you can park at the free parking offered by sheplers. They have three lots. You can buy your tickets right before the boat or you can go online at www.sheplersferry.com. I know adult tickets are 25 and I think children tickets are 15. The trip to the island is about 15 minutes. If you have any other questions just let me know.
Only way: a ferry. I recommend sheppler's. Unless you're awesome and flying to the island direct, which you can do. But I have idea how to.
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