Port Resolution tide times

Port Resolution is a sheltered bay on the eastern coast of Tanna Island, Vanuatu, separated from the open South Pacific by a narrow northeastern passage. The bay is the former anchorage of HMS Resolution in August 1774, when Captain James Cook recorded detailed observations of both Mount Yasur's eruptions and the Tannese people in what was to become one of the most documented first-contact accounts in Pacific exploration history. The name has stuck for 250 years.

Geologically, the bay is a submerged volcanic caldera — the rim of an ancient eruption vent that partially collapsed and was subsequently flooded by the sea. The circular shape of the bay reflects this origin, with black lava cliffs forming most of the rim and the narrow passage to the east as the collapsed section. The black sand beach on the western shoreline is volcanic material, fine-grained and dark, warm underfoot in direct sun. The beach is protected from southeast trade wind swell by the bay's orientation and the surrounding cliffs; conditions inside are calm even when the open coast outside is rough.

The tidal regime at Port Resolution is mixed semidiurnal, with a spring range of approximately 1.0 to 1.2 metres. Tidal current inside the bay is gentle — the bay volume is small relative to the passage opening, and the exchange rate is slow even on spring tides. The current through the northeastern passage on the flood and ebb is more noticeable: 0.5 to 0.8 knots at springs. Kayaking in the bay is straightforward at all tide states; the passage to the open sea requires assessing conditions outside before committing.

Thermal vents on the bay floor are the distinctive feature for snorkellers. The vents are located in 3 to 8 metres of water and create visible temperature anomalies — patches of water noticeably warmer than the ambient 25 to 27 degrees Celsius of the bay. The shimmer effect above each vent is visible to the naked eye from the surface on calm days. The bottom around the vents is volcanic rock and rubble; a sparse but resilient marine community of crabs, small fish, and encrusting organisms occupies the surrounding substrate. Coral growth near active vents is suppressed by the altered water chemistry (elevated CO₂, slightly reduced pH), but the outer bay walls have better coral development.

For photographers, the combination of the black sand beach, the surrounding black lava cliffs, and the volcanic interior landscape behind makes Port Resolution compositionally striking at dawn and dusk. The Yasur glow — visible on the mountain horizon after dark, intensifying as eruptions occur — is photographable on clear nights from the beach and from the bay anchorage, using a long exposure and a stable tripod.

Kayaking from the beach into the passage and out to the open coast is possible in calm conditions; the open eastern coast of Tanna faces the South Pacific and can be rough in trade wind conditions (May to October). The bay offers a protected base with easy access to the coast in settled weather. Community guides available in the Port Resolution village offer boat tours of the bay and access to the outlying coastal viewpoints.

Predictions on this page come from Open-Meteo Marine, a gridded global ocean model. Accuracy is typically within plus or minus 45 minutes on timing and 0.2 to 0.3 metres on height — model-derived, not from a local gauge. The local tide authority is the Vanuatu Meteorology and Geo-Hazards Department (VMGD).