Open Water Swimming: Training for the 33km Ocean Marathon at Sunshine Swim

Open water swimming continues to gain popularity among endurance athletes seeking challenges beyond the pool. One such endeavor drawing attention is the 33km ocean marathon swim, a feat requiring immense physical and mental preparation. Athletes like Bronte Matthews, who shared on Instagram in March 2026 that she doesn’t run but swims very long distances and often runs out of snacks during training, are currently preparing for this exact challenge – the Sunshine Swim.

The Sunshine Open Water Swim Series, held in Florida’s Tampa Bay area, features multiple events throughout 2026, including a notable 10K race. According to event details from RunSignup, the Sunshine Open Water Swim took place on March 7, 2026, at Pass-a-Grill Beach in Saint Petersburg, FL. This event offered various distances, including a 10K swim structured as two 5K loops, alongside 5K, 1.2-mile, and half-mile options. Open to swimmers aged 7 to 90, the series emphasizes inclusivity and community, with participation capped at 150-200 athletes to maintain an intimate atmosphere.

Whereas the March 7, 2026 event included a 10K distance, the 33km ocean marathon swim referenced by athletes like Matthews represents a significantly greater challenge, exceeding standard race distances in the Sunshine Series. Training for such an ultra-distance swim involves months of progressive overload, focusing on building aerobic capacity, refining open water navigation skills, and practicing fueling strategies for prolonged exertion – hence the common issue of running out of snacks during long sessions.

The Sunshine Open Water Swim Series returns later in 2026 with a second event scheduled for May 16, 2026, at Indian Rocks Beach. Organized by Coach Leo (contact: owsleo11@gmail.com), the series aims to grow thoughtfully while preserving its core spirit of pushing limits and sharing the open water experience. Events feature staged starts to accommodate different distances smoothly, and the series welcomes sponsors interested in supporting this passion project.

For athletes targeting extreme distances like the 33km ocean marathon, events in the Sunshine Series serve as valuable training milestones. Shorter races allow swimmers to test equipment, pacing, and mental resilience in open water conditions without the cumulative fatigue of longer efforts. As interest in marathon swimming grows, series like this provide accessible entry points and progressive challenges for swimmers of all levels aiming to push their boundaries in the sport.