US Navy Seal Team Eighteen Challenge Coin. Very hard to come by Seal Team Eighteen challenge coin. If you are a challenge coin collector this is a must have coin for your collection. Pleease check my other listings for some more great coins. I will continue to post in the future with more coins. The item “US Navy Seal Team Eighteen Challenge Coin” is in sale since Monday, December 2, 2019. This item is in the category “Collectibles\Militaria\Current Militaria (2001-Now)\Original Items\Challenge Coins”. The seller is “itsmekurtr” and is located in United States. This item can be shipped to United States.