Monterey/SF would be my recommendation for that interest, particularly with the aquarium, but you can definitely find seals in Maine and it's beautiful (I assume the same is true for the Canadian coast, but haven't been). Maybe post this on the r/travel sub - there's a lot more people on there.

Any state/province on the west coast. You’ll find gray seals in the Maritimes, but that’s about it for pinnipeds.

San Diego/ La Jolla.

Entire Sea Lion rookery, as well as seals. I know, California. But it’s guaranteed.

Fitzgerald Marine Reserve in Moss Beach (near Half Moon Bay). About 30 mins south of San Francisco.

Sometimes docents are on hand to give some interesting insights and the tidal pools can be really fun to explore (check tide tables).

Please make sure to give the sea lions a wide berth, they need lots of distance.

Non-touristic? Monterey. There’s a Coast Guard station with a pier near Monterey Fisherman’s wharf. Always tons of seals and sea lions there.

https://maps.app.goo.gl/vLiCSy6CpyCfpzTc6?g_st=ipc

Yeah, it’s kinda touristic, but nothing compared to San Francisco’s fisherman’s wharf.

If going to Santa Cruz you can also hit Año nuevo state park and see some elephant seals too

The Marine Mammal Center is a research and rescue located in Sausalito. Tours are free but need to book a reservation. 

https://www.marinemammalcenter.org/visit/getting-here

You can take a ferry from SF to Sausalito.  Downtown Sausalito is a great place for lunch, shopping and galleries 

The Sea Lions off Pier 39 operate their own schedule but dozens, if not super groups hang out there daily.

Pier 39 or there are a dozen that usually hang around the Ft Mason Marina.

Take a whale watching tour out of newport harbor.

Sea lions hang out on docks and even boats around the harbor

There were a lot of sea lions at Dana Point Harbor by the boat docks. It was very entertaining to watched as they were barking, fighting (chest bumping), & splashing around. But I’m not sure if they are still there as we saw them few weeks ago.

Dana Point Harbor

This place

https://www.pacificmmc.org/

• Pacific Marine Mammal Center (you'll need to call to confirm current patients & if they're visible to the public & maybe see if you can find out if they're having a release that coincides with your visit)
• Crescent Bay Beach: Off the north point there is a large rock about 120 yards offshore called Seal Rock because of the seals and sea lions that take refuge there
• Sea lions and seals love to bask and sleep aboard the floating ocean platforms, and are also known to frequent Dana Point Harbor and nearby Newport Beach Harbor - See CA

Have a lovely pre-baby day!

There are dolphins just off shore at Santa Monica pretty regularly. Not predictable but they move up and down the coast about 50 to 400ft out.

Sea lions hang out inl Marina del Rey harbor. There is a fishing bait barge permanently mored in the channel. They are there all the time.

You're likely to see at least a few sea lions sunning themselves in the marina at Marina del Rey, but dolphins are unlikely unless you're out on the water with a whale watching tour or something.

On the boat to the Channel Islands.

LA Zoo

Marina del Rey for the Sea Lions. They often hang near fisherman's village on the docks. They also hang out in the channel inlet and beg for food from the passing boats. There's a pod of dolphins that cruises the shoreline in Santa Monica, and when I see them, it's usually between SM canyon and Gladstone's. If you spend the day at the beach there-abouts, I'd say you've got a decent chance. Short walk from the parking lot either way.

Yes, MDR around Burton Chace or the LMU boat house are usually good bets. Ask a paddleboarder if they’ve seen any that day. I usually do every time I paddle in MDR.

There’s also a buoy near the SM Pier where they like to chill.

Redondo Beach around the pier, I see at least one every time I go.

Channel Islands Harbor (Oxnard) or Ventura Harbor has lots of them. Easy free parking too.

La Jolla

i saw 6-8 there yesterday...no guarantee they'll be there in february. they're usually near 'burton chace park'.

"sea lion rock" aka Brin rock by the discovery island lighthouse every year in may.

You can often see them chasing sea antelope across the sea Serengeti

Fyi sea lions stink like compost and manure

I used to see them hanging around on the science buoy in Pat Bay, inland side of the peninsula. Was pretty funny to sail close. The big ones didn’t budge. And oh, yeah, the stink. Wow.

Ive seen them barking and swimming around out at Macaulay point park (which is worth a visit even without guarantee of sea lions and not too far of a bus ride on the 25!) If you hang out at the beaches around Dallas road that face port angeles you might see some too

They are all over the dock across from Old Town and fishing/hunting around the confluence of American and Sacramento rivers.

Check out the Delta King Hotel! If you walk in through reception straight through to the river side of the boat (this has always been ok in the past, but be respectful of guests and try not to be loud) you can see the sea lions that lay on the dock on the opposite side of the river most days.

You can also see it from the boardwalk in Old Town Sac, but the boat is just a fun thing to check out. They have a bar on the top floor and a restaurant in the middle that are open to the public.

Actually, was just commenting that we hadn’t seen them on the river or the docks lately

Been a few weeks since I've seen any.

You'll see them more often in the fall when they are chasing the salmon. They hang out on the docks around Old Sac near Tower Bridge.

For seals you will want to go to Woodard Bay conservation area, take the trail north to the pier, that is a spot where seals will be, if you have a kayak or paddleboard that would be a plus. Sea Lions I believe are a rarer sight here but they do show up sometimes and sun bathe or sit on boats https://youtu.be/Jnw1sDmiwhk

Tolmie state park is also a great spot for marine life.

For whale watching you are going to want to be farther north by port angeles, there are lot of whale sightings going on right now https://www.king5.com/article/tech/science/environment/orcas/70-biggs-whale-salish-sea/281-2ee7580a-a42a-498f-90dd-fbb3accb758a

In the summer, we get bioluminescent algae in Puget Sound. I like to go up to Boston Harbor at night and stir the water to see it.

That's a great idea! I'm going to make a note. A natural salmon run must be incredible in person.

Northwest Trek outside of Eatonville, Washington.

https://www.nwtrek.org/

Billy Frank Jr. Nisqually Wildlife Reserve. I've seen many different birds, seals, sea lions, otters and more.

This is a terrific place to see beaver, too, along with turtles and birds common to lakes and ponds.

We do have Harbor Seals. I've had most luck at either Cornwall beach or the ferry terminal, but it's really hit or miss.

If you drive north about 30 min, there's a colony of about 100 seals that haul out on the far end of the dock at Semiahmoo Spit. You can get fairly close if you walk out at low tide, otherwise bring binoculars! Also, Blaine is super cute and I find that my visitors always get a kick out of seeing the Canadian border.

I'm not sure if the salmon are running, but if they are, that's where the seals will be. I used to see them all the time by what is now the Granary building where Whatcom Creek debouches. Sometimes they even make it up into Maritime Heritage park when the eats are good.

The best place by far is the Whatcom creek inlet, specifically next to the waterfront bar and grill. They also go further up the creek to the hatchery area, I was there the other day and saw 5 seals so I’m assuming salmon are in the creek.

You’ll mostly see harbor seals around the bay. Marine park, Maritime Heritage park, the ferry terminal and boulevard park are all good options to see them in a daily basis.

However, if you’re looking around salmon season (around now!) you can occasionally find a HUGE sea Lion chasing salmon up the mouth of Whatcom creek at maritime heritage. I watched a huge ripple the size of a car go underwater chasing salmon until a giant snarly sea Lion reared it’s head at the shore! Quiet a sight to see.