Welcome to SimV,
All of the default seaplane bases are in the airport and gps database. They can be used as starting points (Select Airport) or as Flight Plan or GPS Direct To destinations. The MSFS-FSInsider article, 'Water Water Everwhere' has a .pdf download listing all of them-
http://www.microsoft.com/Products/Games/FSInsider/freeflight/Pages/WaterWaterEve.... Nearly all are in the U.S., none in Canada.
Few, if any, include scenery.
If you looking for add-ons, a few notables are....
By Chris Carel ('Mocat')-published 3 series that include many seaplane bases with scenery:
-Caribbean Seaplane Tours-several downloads that cover Florida and the Caribbean.
-Land's End Seaplane-4 downloads that cover the US coasts and northern border.
-Snow Dog Tours-BC and SE Alaska coast. Look for 'Snow Dog Tours v2.0, which combines the original 3 part release into one download.
Holger Sandmann, et al.-FSX Victoria-Victoria, Canada Area, including the Southern Gulf Islands and the San Juan Islands of the US. 2 part download.
Dave
At that time [1909] the chief engineer was almost always the chief test pilot as well. That had the fortunate result of eliminating poor engineering early in aviation. Igor Sikorsky
I intend to live forever....so far, so good. Steven Wright
You know....you can just rip up a to-do list.