There are several Boston restaurants that offer a waterfront patio with stunning views of the harbor. Here are a few notable options:

1. The Barking Crab - Located on Sleeper Street, The Barking Crab is a popular seafood spot with a spacious patio overlooking the harbor. It's known for its fresh seafood dishes and relaxed atmosphere.
2. Legal Harborside - Situated on Northern Avenue, Legal Harborside is a three-story restaurant with a rooftop patio that offers panoramic views of the harbor. It serves a variety of seafood and New England-inspired dishes.
3. 75 on Liberty Wharf - Located on Liberty Wharf, this restaurant features a spacious patio overlooking the harbor. It offers a diverse menu with options ranging from seafood to steak and has a trendy, upscale ambiance.

These are just a few examples, but there are many more Boston restaurants with waterfront patios that provide a picturesque dining experience. It's always a good idea to check their websites or make reservations in advance to ensure availability.