Open daily for lunch 11:30 a.m. to 5 p.m.; for dinner 5 p.m. to 1 a.m. Sunday through Thursday, until 2 a.m. Friday and Saturday. AE, MC, V. No reservations accepted. Prices: For lunch appetizers $3 to $4, entrees $6 to $7; for dinner appetizers $3.50 to $12.95, entrees $7.50 to $16.50. Full dinner with wine or beer, tax and tip about $25 to $30 a person.

In restaurants, as with people, it helps to know their origins. You could easily steer yourself wrong at the Blue Channel Inn, for instance, if you didn't know that this place is a sibling of a small crab house near Annapolis. That should serve as a clue for what to order: crab, crab and more crab. Your introduction to the Blue Channel Inn is likely to be the cocktail lounge, for the restaurant takes no reservations and always seems to need at least five minutes to call you to a table -- just long enough to encourage you to order a drink. It's actually not a bad idea, since the bar stocks a decent selection of imported beers and makes a mean bloody mary -- mean with horseradish and cleverly garnished with a spiced shrimp. In fact, many people seem just to stick to the bar, and there is a menu of snacks to keep them fueled.

The dining room is right on the water, but unfortunately you might not know that if you hadn't read it here, for only the tables on the glassed porch have an unimpeded view, and even that is disrupted by glare that turns the glass into a reflecting pane. Nevertheless it is a pleasant dining room for such a cavern of a place. There is a fireplace to be viewed from both the porch and indoor dining rooms, and while the high ceiling and exposed ductwork create an acoustical problem, the carpet somewhat alleviates it. In all, the room looks like a polished- up boathouse, pretty but casual, with the daily specials on a blackboard and no cloths on the tables.

Blue Channel Inn keeps trying to fool you into thinking it has an indifferent kitchen. It serves crackers with a little metal cup of insipid cheese spread and doesn't even bring bread so you can sop up the nice pan sauces. Its salads are handsome, icy platefuls of shredded carrots, dark crisp romaine, cherry tomatoes and onion rings with croutons, but the dressings are gummy thick and tend to be way too sweet or way too sour. And it is hard to take seriously a seafood house that has chicken noodle as its Friday soup of the day.

But there is some very good food lurking on the overambitious menu. Start right in with crab meat, stuffed into mushroom caps. The crab is sweet, fresh and carefully handled, mixed imperial style with mayonnaise and mustard, just enough to enhance rather than drown its flavor. The stuffed mushrooms are nicely browned and the filling not overcooked. Steamed mussels, too, are cooked just enough to be plump and juicy and flavorful, with garlic butter for dipping. At $4.50 for two dozen, they are also a bargain. And removed from their shells to be served in basil butter sauce they are not quite as good as they are plain, but they are still pleasant. Oysters and clams on the half-shell are also available, or they can be had steamed -- although I don't recommend them.

You'd think a kitchen that did well with stuffed mushrooms could fry a clam nicely, but no such thing. The fried clams are frozen, heavily breaded and fried into stiff, tasteless sticks. And spicy crab vegetable soup, a Maryland classic, needs more spice, more crab and more fresh-tasting vegetables.

If you stray so far as broiled trout, swordfish or flounder, you are likely to encounter fish with a bitter aftertaste, caked with paprika and sometimes cooked to unnecessary firmness. Even though swordfish and trout were daily specials, they were chewy and tasteless. Furthermore, the menu is generally limited to bout three fish: salmon, flounder and a special such as the swordfish, trout or monkfish. Given those oceanic disappointments, I didn't want to challenge this seafood restaurant further with chicken or steak. There are also sandwiches and "light fare" (boneless fried chicken breast, clam fry, fried shrimp or flounder) for under $6, so admittedly the risks are only moderate at the Blue Channel Inn. The seafoods include scallops or mixed seafoods in white wine and garlic butter, seafood norfolk (an unorthodox rendition that includes mushrooms, tomato, green pepper, onion, bacon, sherry and garlic), fried shrimp or oysters and combination plates, steamed, broiled or fried. So it is a mix-and-match menu, but most of the mixes include items you'd best avoid. Take the Captain's Choice, broiled flounder (bitter), broiled scallops (all right), fried oysters (leaden), butterfly shrimp (stolid), fried clams (those chewy strips) and crab cake. It all boils down to your wanting more of the crab cake, which is light and deftly made, with excellent lump crab and not much else, fried so that the surface is lacy crisp and not greasy. The next time you might just as well order the crab cakes on their own. The same story is to be told about the steam pot of lobster, cherrystone clams, mussels, shrimp and oysters: It looks cute, tumbling out of a small metal basket, but while the lobster has cooked, everything else has overcooked. You are better off with a plain lobster, though even that had a less distinguished texture -- part chewy, part mushy -- than taste, which was sweet enough. The tale repeats with stuffed flounder, oysters or shrimp, which are merely a vehicle for that excellent crab imperial, and you might just as well enjoy that unadulterated.

With those main dishes come a very good baked potato -- baked without foil -- or fine french fries with the skin on, or a mild, creamy and very satisfactory coleslaw. Or that lovely salad. There are also fresh vegetables, usually overminced zucchini and carrots that are a buttery mush.

As for desserts, the servers make them sound stupendous (but then those extraordinarily enthusiastic servers could make anything sound stupendous). In reality they are extremely sweet and rather gooey versions of chocolate cake, chocolate pie and other cakes such as Grand Marnier or mocha, but their names -- The Great American Chocolate Cake, for instance -- have far more punch than their flavors. The wine list is short, but the choice and prices are not bad. And the espresso is surprisingly good for a seafood restaurant.

In short, the Blue Channel Inn has brought better eating to Reston than has almost any other restaurant, in a pleasant casual dining room and served with the flair and enthusiasm of a chorus line. It just takes some careful picking and choosing with an unwavering eye on Chesapeake Bay tradition to assure yourself of the kitchen's best.