Owl Harbor Marina

Owl Harbor Marina is a gated, park-like marina of about 20 acres on Sevenmile Slough off the San Joaquin River, at channel marker 41, near Isleton and Rio Vista. It is on Twitchell Island at 1550 West Twitchell Island Road and houses roughly 200 vessels. The marina is part of the Delta Loop, and it markets the fact that there are no drawbridges to pass on the way from the Bay Area.

Berths

Owl Harbor rents open slips, end ties, covered slips, wide multihull slips and side ties. Covered slips are offered for boats up to 36 feet. Side ties without power or water are capped at 24 feet. The marina lists open-slip rates per foot of length overall that are lower from November to April than from May to October, and a higher per-foot rate for catamarans and other multihulls.

Guest docks and grounds

Guest docks are available, and the marina's booking listing shows check-in after 1 p.m. and check-out by 11 a.m. The grounds have a 24-hour fitness room, free Wi-Fi, heated showers, laundry, picnic tables, barbecues, horseshoe pits, a community organic garden and loaner kayaks, stand-up paddleboards and bicycles. Pets are welcome.

On the water

The marina describes seals and birds, levee walks along the San Joaquin River and Mount Diablo sunsets. Highways 12 and 160 lead to it by road; there is no public launch ramp listed here, so trailer boats launch elsewhere.