Deephaven Beach, which the City of Deephaven also calls Deephaven Main Beach, is the largest of the six public swimming beaches the city runs on Lake Minnetonka. It sits at 19405 Lake Avenue on the east side of St. Louis Bay, one of the deep bays that form Deephaven's western edge, roughly 15 miles west of downtown Minneapolis. The city's recreation pages describe it as its most versatile beach, and it is the only one of the six with lifeguards.

The beach is on Lake Avenue in the northwest corner of the city, a short drive from Minnetonka Boulevard. Getting in costs nothing. The city says its beaches are open to residents and non-residents alike, but the lot beside the beach is signed Parking by Permit Only from May 1 to October 1, and the rule is patrolled. Deephaven residents get stickers in the mail. Non-residents can buy a season beach parking sticker for $60 in person at City Hall (20225 Cottagewood Road), or a $120 sticker that also covers the Carson's Bay boat launch. Vehicles with a state disability parking permit can use the permit lots without a city sticker. If you don't want to buy a sticker, the city points visitors to free on-street parking wherever there is no No Parking or permit-only sign. The Northome Trail, a walking path along Northome Road from Chowen's Corner at Maplewood Road and Minnetonka Boulevard, ends at the beach and is the easiest way in on foot or by bike.

The swim area is a broad sandy beach facing west across St. Louis Bay, with a swimming dock. This is a sheltered bay, not open lake, so there is no current to speak of, though wind from the west can push a chop onto the beach. Lake Minnetonka warms slowly in spring and is usually at its most comfortable from July into August. The most recent schedule the city has posted puts lifeguards on duty Wednesday through Sunday, 11 a.m. to 6 p.m., into late August. Outside those hours and days you swim unsupervised. Like every Deephaven park, the beach is closed from midnight to 6 a.m., and city rules allow dogs only at Thorpe Park, so leave them home.

Hennepin County takes water samples at Deephaven Beach every week in summer and tests them for E. coli. When a result is over the EPA limit, the county recommends closing the beach and samples again the next day, and the Lake Minnetonka Conservation District notes that short closures like this happen on the lake most summers. Check the county's beach water quality map before you go, and give the water a day after a heavy rain. The St. Louis Bay boat launch is right next to the beach. The city closes it from about Memorial Day to Labor Day because it is so close to the swim area, but expect boat traffic on the bay itself, particularly near the city's moorings just north of the sand.

The park around the beach has a sports court, swings, a sun arbor, a picnic area with a grill, and canoe racks (the racks are rented to residents). Tennis courts sit just inland. Deephaven's other beaches, including Robinson's Bay, Sandy, Rocky and Nocomo, are smaller, have no lifeguards, and have very little parking, so Deephaven Beach is the one to pick if you are coming from out of town.