Kwun Mun Sea Cave

🪨 【Kwun Mun Sea Cave (官門遺洞)】, located at the East Dam of the High Island Reservoir in Sai Kung , was originally a part of the old “Kwun Mun Channel.” It is a natural sea cave carved out by continuous wave erosion. When the High Island Reservoir was constructed, it was cut off from the open sea by a massive breakwater, allowing the cave structure to be perfectly preserved to this day. It stands as a vital historical testament to the former “Kwun Mun Channel” while showcasing iconic coastal erosion landforms alongside magnificent hexagonal volcanic rock columns. Today, it serves as a highly popular destination for tourists and geology enthusiasts alike, anchoring itself as a core attraction within the Hong Kong Geopark. —

📌 General Information

Item	Description
📍 Location	Sai Kung District, High Island Reservoir East Dam
🏔️ Surrounding Topography	Bounded by Biu Tsim Kok to the north; bordered by Fa Shan to the south; overlooks the spectacular hexagonal rock column cliffs of Po Pin Chau to the east.
📜 Historical Background	Originally formed part of the “Kwun Mun Channel,” a busy waterway separating High Island (Leung Shuen Wan) from the Sai Kung Peninsula. Following the completion of the High Island Reservoir in 1978, the channel was blocked off by the main breakwater, leaving this structure preserved behind as the “Kwun Mun Sea Cave.”
🌊 Geological Formation	Long-term wave action eroded the weak points along the volcanic rock face, eventually hollowing it out into a sea cave.
🪨 Rock Characteristics	The cave entrance and its surrounding walls prominently feature hexagonal volcanic rock columns, a textbook example of thermal contraction structures formed during the cooling of volcanic matter.
🛡️ Conservation Status	Protected by the massive concrete breakwater, wave action has ceased to erode the site directly, allowing the cave’s original structural profile to remain completely intact.
🌉 On-site Amenities	Outfitted with an elevated wooden boardwalk, allowing visitors to approach and view the cave opening safely up close.

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🌟 Scenic Highlights

• Kwun Mun Sea Cave: A striking natural sea cave with a grand and dramatic opening.
• Po Pin Chau : A magnificent wall of contiguous hexagonal rock columns that closely resembles a giant pipe organ.
• Long Ke Wan: Boasts fine white sand and pristine camping grounds, widely regarded for its exceptional scenery.
• Kim Chu Wan: A pebbled shore where the action of breaking waves creates a unique rolling rattle sound over the stones.
• High Island Reservoir East Dam : A captivating intersection of monumental engineering breakwaters and raw coastal wilderness, highlighting the relationship between mankind and nature.

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🗺️ Geological & Cultural Significance

• Geological Value: Showcases Hong Kong’s globally rare hexagonal columnar jointing structures within volcanic tuff, recognized as a world-class geological phenomenon.
• Cultural Background: The former Kwun Mun Channel was once a crucial shipping lane; the cave has now become a physical monument to the pre-reservoir landscape.
• Tourism Value: Now safely integrated within the Hong Kong UNESCO Global Geopark, it stands as a major draw for geologists, photographers, and outdoor hikers alike.

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🥾 Hiking Trail Guide: Kwun Mun Sea Cave Po Pin Chau Long Ke Wan

📍 Route Overview

• Starting Point: Sai Kung Town Centre → Take transport directly to High Island Reservoir East Dam
• Key Landmarks:
  1. Kwun Mun Sea Cave
  2. Po Pin Chau
  3. Long Ke Wan
• Finishing Point: Long Ke Wan → Return to Sai Kung Town Centre

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🌊 Trail Attractions

• Kwun Mun Sea Cave
  • A grand natural sea cave showcasing majestic hexagonal column formations layered inside.
  • A living relic of the historical “Kwun Mun Channel,” complete with an accessible wooden boardwalk for upfront sightseeing.
• Po Pin Chau
  • Features a dramatic, organ-like wall of hexagonal jointed rocks, serving as an iconic postcard site for the Hong Kong Geopark.
  • A striking islet completely sheared off from the main headland, offering breathtaking, dramatic views.
• Long Ke Wan
  • One of Sai Kung’s most famous pristine beaches, known for its ultra-fine white sands and crystal-clear turquoise waters—perfect for coastal camping and water recreation.
  • Frequently lauded as “one of Hong Kong’s most beautiful beaches.”

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🗺️ Route & Time Schedule

Section	Time Duration	Difficulty	Notes
Sai Kung Town Centre → High Island Reservoir East Dam	Approx. 40 mins ride	🚗	Accessible via urban/New Territories taxis, chartered transport, or the weekend/holiday designated shuttle bus service.
East Dam → Kwun Mun Sea Cave	Approx. 15 mins walk	⭐ Easy	Flat, paved pathways connecting straight to the wooden boardwalk.
Kwun Mun Sea Cave → Po Pin Chau	Approx. 20 mins walk	⭐⭐ Moderate	Requires trekking past the breakwater and up unpaved dirt trails; certain sections are rough and rocky.
Po Pin Chau → Long Ke Wan	Approx. 1 hour walk	⭐⭐ Moderate	Steep downhill mountain path; step carefully while enjoying the sweeping ocean views along the ridge.
Long Ke Wan → Sai Kung Town Centre	Approx. 40 mins ride	🚗	Requires hiking back up to the East Dam pavilion to hail a taxi, or pre-booking a chartered vehicle or speed boat transfer.

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🎯 Difficulty Grading

• Kwun Mun Sea Cave: ⭐ Easy (Perfect for family day trips)
• Po Pin Chau: ⭐⭐ Moderate (Requires attentiveness over loose, rocky cliff trails)
• Long Ke Wan: ⭐⭐ Moderate (Features continuous downhill trails; demands reasonable physical stamina)
• Overall Route: ⭐⭐ Moderate; the entire journey takes about 3–4 hours (excluding transit times).

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Transit Options

• Reaching the Trailhead (Sai Kung Town Centre → East Dam)
  • Taxi / Chartered Van: The most direct method, taking roughly 40 minutes.
  • Green Minibus / KMB Geopark Shuttle Bus: Regular public services and designated tourist bus routes run directly from Sai Kung Town Centre to the East Dam (primarily operational on weekends and public holidays).
• Return Journey (Long Ke Wan → Sai Kung Town Centre)
  • Walk back up to the East Dam area to take a return taxi.
  • Alternatively, make arrangements for an authorized marine speedboat pick-up straight from the beach back to Sai Kung Pier.

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⚠️ Important Reminders

• Ensure you bring plenty of drinking water, snacks, and proper sun protection, as there is minimal shade on the dams.
• There are absolutely no retail stores, kiosks, or mains water supply points at Long Ke Wan; you must pack in your own food and supplies.
• Portions of the mountain track are highly rugged and unpaved; sturdy hiking shoes with solid grip are strongly advised.
• In periods of adverse weather, heavy rain, or high ocean swells, keep a safe distance from open rock faces and sea caves.