I have no idea how to do it in Illustrator but here's how to do it in Photoshop...I assume it would be similar enough so that you could figure it out.

First I have the land on its own layer. On a new layer I draw a big blob of color that extends out into the ocean while the part on land follows the shape that I want. Ctrl+click on the land layer and select-inverse then hit delete...this deletes the blob out on the ocean so that the blob now has a "country" shape. Ctrl+click on this layer and on the paths tab hit "path from selection". On a new layer you stroke the path and voila, then you can dump the country layer beneath if you like.