Just about “all the beaches at the “National Seashore have great viewing”, for seals! I have observed them at “all the beaches from Chatham to P’town!” Honestly, the more crowded the beaches are( especially during high season) the less chance of seeing seals but no matter how busy it is you are still bound to catch a glimpse or two of seals bobbing in the ocean waves( so fun to watch)! Chatham( near the lighthouse) has the most and if you go around five or six pm you are bound to see lots, in particular! Just stand up in parking lot, looking down and you will see them! Nauset Beach & Coast Guard Beach, at the National Seashore in Eastham had the most! They were swimming right beside my son surfing, not afraid at all. They seemed to come out in droves around five pm when each was more deserted but they were still there mid-day, too! We saw them at Marconi Station in Wellfleet ( lots), as well. We rented a house in Truro last yr in June and probably five or six were surfing in waves astone’s throw from our chairs!when my sisters and I went into the water( almost no one else there) the seals remained almost beside us! They were not afraid at all! We go out to Cape Cod several times a year for over 50 plus years now, all seasons and different times...we love the Cape so much!!!! If you go to Nauset or Coast Guard Beach in Eastham or Marconi Beach( definitely stop and see the “White Swamp” tucked to left of beach road if you go there! Amazing to see and “Marconi Station!” You will love the “WHITE CEDAR SWAMP”... boardwalk and everything!) P’town ( Race Point) had seals too but I recommend the other three heavily, first! You can observe them pretty much at all the beaches but as I said before Nauset and Coast Guard Beach in Eastham are the best beaches! Go to Chatham to just “observe them!” Enjoy!