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Map of White Horse Beach (Flag Rock)
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Shore entry

White Horse Beach (Flag Rock)

Massachusetts, United StatesDirections
Open Water suggested2–9 m depthShore entry5mm wetsuit typical

White Horse Beach (Flag Rock) at a glance

White Horse Beach (Flag Rock) is a shore dive site in Massachusetts, United States with depths of 1.5–9.1 m (5–30 ft). Typically most favorable Jul–Aug · from 3 years of archive data. Divers commonly see Striped bass, Northern sea star, and Rock crab. Recent reports put the water around 19°C (67°F). Check the latest conditions and entry details before you go.

Marine model · graded 1h ago
0.2 mwaves — under half a meter expected

Tap a factor for its source and model point · Forecast 19°C · seasonal avg 19°C

Site hazards: Shallow rocky bottom around Flag Rock with surge on onshore (easterly) winds; cold water; summer swimmers; very limited legal parking in season.

Read the full hazards ↓

Dive windows this week

Best: Thu
Fri14:00–19:00
Sat7:00–19:00
Sun14:00–19:00
Mon7:00–19:00
Tue12:00–19:00
Wed7:00–19:00
Thu7:00–19:00

Favorable windowModerate window— no window

First light 5:50 · Sunrise 6:18 · Sunset 18:59

Source: Open-Meteo marine · model point 12 km from site · graded 1h ago

Forecast only — always assess conditions on site.

Forecast · NOAA tide model

Tide & slack timing

Loading tide predictions

Recent diver reports

Dated firsthand observations from divers — not current conditions.

No diver reports for this site yet. — one dated observation helps every diver after you.

Dived here today — did the forecast match?

What Divers Say

Known for: Northern sea star, Rock crab, Hermit crab
Best time: At or near high tide (maximum depth ~30-35 ft only on the highest tides); calm days without onshore easterly wind; off-season for easy parking. Locally regarded as a good beginner or shakeout dive.

Based on community reviews and site data. Conditions vary — always verify before diving.

Best months, historically

What conditions have historically been typical at this site, month by month — not a forecast.

  1. Jan84%5°C0.9 m
  2. Feb82%4°C0.8 m
  3. Mar81%4°C0.9 m
  4. Apr92%7°C0.7 m
  5. May96%11°C0.6 m
  6. Jun96%16°C0.4 m
  7. Jul100%18°C0.3 m
  8. Aug100%19°C0.4 m
  9. Sep93%19°C0.5 m
  10. Oct90%16°C0.7 m
  11. Nov90%11°C0.7 m
  12. Dec88%8°C0.8 m

July and August havetypically had the largest share of favorable days here. Conditions vary year to year — this is historical context, not a forecast.

Based on 3 years of archive data. Bar height shows the share of days each month whose conditions have historically scored favorably.

Marine life seen at this site

Species noted at this site — not a promise of what you’ll encounter.

Species seen here

Fills & rentals nearby

No dive shops mapped within 25 km. Know one? Add it to the map.

Data updated July 2026

Site details

White Horse Beach in the Manomet section of Plymouth is a shallow Cape Cod Bay shore dive centered on Flag Rock, the landmark boulder at the north end of the beach that has carried a painted American flag since 1941. The rocky bottom around the rock holds lobsters and typical New England bay life in roughly 10-30 ft of water - about 35 ft is possible only on the highest tides - making it a good beginner or cobweb-shakeout dive. Average visibility runs around 16-20 ft. Summer parking is the main challenge, with resident restrictions near the beach.

reefshore

Shallow rocky bottom around Flag Rock with surge on onshore (easterly) winds; cold water; summer swimmers; very limited legal parking in season.

Reviews

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