2025 Shonan International Marathon

The 2025 Shonan International Marathon takes place on December 7, 2025, in Oiso, a coastal town south of Tokyo, Japan. Early December in Oiso typically brings mild winter weather with temperatures ranging from 8-15°C (46-59°F), with relatively low precipitation and clear visibility—ideal conditions for viewing the scenic Shonan beachfront. Participants can expect a flat, straight marathon course with stunning vistas of Mt. Fuji and nearby attractions, combined with an innovative zero-waste hydration system that represents a significant advancement in sustainable event management. The race features 200 water stations positioned every 200 meters along the course, allowing runners to refill personal bottles and cups while minimizing environmental impact.

What is the course layout and terrain like?

The Shonan International Marathon features a flat, straight course with only two major turns and just 15 meters of elevation difference throughout the entire race. The route runs along the scenic Shonan beachfront south of Tokyo, starting and finishing in Oiso. Participants will enjoy stunning views of Mt. Fuji during the race, with nearby sightseeing attractions including Kamakura, Hakone, and Yokohama visible from various points along the course.

What race distances are available?

• →Full Marathon
• →10km Fun Run
• →2km Fun Run
• →1.4km Run and Walk

What is the eco-friendly hydration system?

The 2025 Shonan International Marathon features a revolutionary "My Cup / My Bottle Marathon" approach that eliminates disposable cups and PET bottles entirely. The course includes 200 hydration stations positioned at 200-meter intervals, supplied with approximately 40 tons of water delivered via:

• →20-liter stainless steel jugs containing sports drinks and special beverages
• →12-liter returnable bottles containing water
• →2-ton water tanks distributed across the course

This system reduces approximately 6 tons of CO₂ emissions, equivalent to the environmental impact of approximately 170,000 PET bottles. In the 2023 race, this approach eliminated 31,500 PET bottles, 500,000 paper and plastic cups, 26,000 finish-line PET bottles, and associated packaging waste, resulting in a total waste reduction of 8,446 kg.

What are the hydration requirements for each race category?

• →Full Marathon: Must carry a personal bottle with at least 200ml of fluid; a personal cup is strongly recommended
• →10km Fun Run: Must carry a personal cup; a bottle is recommended
• →2km Fun Run: Personal cup recommended (needed for post-finish hydration)
• →1.4km Run and Walk: Personal cup recommended (needed for post-finish hydration)

All participants should label their bottles and cups with their bib number or personal marks to prevent lost property issues.

What sustainability measures are in place?

The marathon implements comprehensive eco-friendly practices throughout the event:

• →Eliminated disposable cups and PET bottles on the entire course
• →Event participant t-shirts made from recycled PET fibers
• →Staff uniforms made from recycled PET fibers (collected and reused after the event)
• →Plant-based material bags for participants
• →Digital programs instead of printed materials
• →Reusable packaging for all event materials
• →Dedicated eco-stations for waste sorting throughout the venue

The 2023 race achieved an 8,446 kg reduction in waste, and 95.4% of participants agreed to continue supporting the eco-friendly approach in subsequent years.

How does the hydration system support disaster preparedness?

The marathon's extensive hydration infrastructure serves dual purposes as both an event resource and a disaster relief system. A formal disaster-prevention agreement has been signed with the local towns of Ōiso and Ninomiya, establishing the 200-station water distribution network as an emergency resource that can be activated during natural disasters or other emergencies affecting the region.

What feedback have overseas runners provided?

International participants have consistently praised the event for several key features:

• →Perfect weather conditions during the race
• →Outstanding Mt. Fuji views and scenic beachfront setting
• →English-speaking master of ceremonies providing clear race communication
• →Clean, well-maintained roads throughout the course
• →Highly supportive and attentive staff members
• →The innovative eco-friendly approach to waste elimination

Many overseas runners have expressed hope that the zero-waste marathon model will be adopted by other major marathons worldwide.

What event gear and materials are provided to participants?

All participant t-shirts are manufactured from recycled PET fibers as part of the sustainability initiative. The event provides digital programs rather than printed materials to reduce paper waste. Participants receive plant-based material bags for carrying personal items. Staff uniforms are also made from recycled PET fibers and are collected after the event for reuse or proper recycling.