Mihama Beach near Osezaki is more suitable for diving and snorkeling than casual swimming due to its rocky, pebble shoreline and underwater topography. The area is known for excellent visibility and diverse marine life, attracting experienced divers. Water shoes are essential due to the rocky bottom. Conditions can vary with weather and currents, so checking local dive shop reports is advisable. Diving should only be undertaken by certified divers or with professional guides. The beach has limited facilities and lifeguard services, so visitors should exercise appropriate caution and preparation.

The best diving conditions at Mihama Beach typically occur from late spring through autumn (May-October) when water temperatures are comfortable and visibility is generally excellent, often exceeding 15-20 meters. Summer offers the warmest water temperatures but can be busier. Autumn (September-November) often provides the best combination of good visibility, comfortable temperatures, and fewer crowds. Winter diving is possible but requires thicker wetsuits or drysuits. Always check local conditions before diving as visibility can be affected by weather, currents, and seasonal plankton blooms.

Mihama Beach is located on the western side of Izu Peninsula near Osezaki Point in Numazu. By car from Tokyo, take the Tomei Expressway to the Numazu area, then follow Route 17 and local roads toward Osezaki (approximately 2.5-3 hours total). Public transportation is limited but possible: take the JR Tokaido Line to Numazu Station, then a local bus toward Ose/Osezaki. Service is infrequent, so check schedules carefully. A rental car is strongly recommended for accessing this lesser-known beach and exploring the surrounding coastal area.

The Osezaki area around Mihama Beach is relatively undeveloped with limited on-site facilities. Several small dive-focused guesthouses and minshuku cater to diving enthusiasts, often providing equipment rental and guided dives. These accommodations typically serve meals featuring fresh local seafood. The nearby Ose district has a few casual restaurants and cafes, but options are limited. Visitors should bring supplies for a day trip or plan meals through their accommodation. Numazu city, about 30 minutes away, offers much wider dining and lodging choices for those wanting more amenities.

Mihama Beach is distinguished by its excellent underwater biodiversity and visibility, making it a hidden gem for divers seeking less crowded dive sites. The area near Osezaki is known for volcanic rock formations creating diverse underwater topography that supports varied marine life including colorful fish, octopuses, and seasonal visitors. Being lesser-known than major dive sites means more pristine conditions and peaceful exploration. The combination of accessible shore diving and interesting underwater landscapes attracts serious diving enthusiasts. Local dive operators provide intimate, personalized experiences unlike busier commercial dive locations.