The Pacific Inn at 600 Marina Drive, Seal Beach, California.

So impressed with this hotel! VERY DOG FRIENDLY!
Long story short, my boyfriend and I (and our 2 dogs) were booked and staying at a different hotel, but were so disappointed with our original booking that after one night we were searching for a new hotel that was TRULY people and dog friendly and didn't drain us for every penny we had. Pacific Inn saved the trip!
The exterior is not the most appealing, but the location is great-just a few blocks from the Seal Beach Pier and Main St., the customer service was excellent, the room was newly renovated and a decent size (the hotel overall is getting renovated), there is no additional charge for parking, and breakfast was offered for FREE. We were most impressed with the pet/dog care box we received during check-in. Yes, a doggy care box. Inside was a couch cover, dog treats (made in the USA), doggy poop bags, doggy pee pads, and a brochure for dog friendly beaches! I couldn't believe it.
I would and will most definitely stay here again- dog(s) or no dog(s).