The largest tides in the world are found in two locations in eastern Canada: the Bay of Fundy, between Nova Scotia and New Brunswick, and Leaf Basin in Ungava Bay, northern Quebec. Both produce tidal ranges around 17 meters (56 feet), dwarfing the global average of just three feet. Which one actually holds the record has been debated for decades.
Bay of Fundy: The Famous Champion
The Bay of Fundy is the most widely recognized extreme-tide location on Earth. Under typical conditions, high tide at the head of Minas Basin reaches about 17 meters (56 feet) above low tide. Near Wolfville, Nova Scotia, the difference between high and low water can hit 16 meters (53 feet) on a routine basis. When storm surges pile on top of normal tidal forces, the range has exceeded 20 meters.
To put that in perspective, twice a day the water level in parts of this bay rises and falls by the height of a five-story building. The tidal currents that drive this exchange are powerful: water rushes through the narrow Minas Channel at speeds between 5 and 8 knots (roughly 6 to 9 miles per hour), flooding and draining a basin that holds about 160 billion tons of water with each cycle.
Leaf Basin: The Overlooked Rival
Leaf Basin, near the Inuit community of Tasiujaq in Nunavik (northern Quebec), produces tides that are statistically indistinguishable from the Bay of Fundy’s. Measurements taken over 311 days recorded a tidal range of 16.8 meters, plus or minus 0.2 meters. The Bay of Fundy’s comparable figure is 17.0 meters, plus or minus 0.2 meters. Those error bars overlap, meaning neither location can definitively claim the top spot based on measurement alone.
That said, Leaf Basin was first recognized by Guinness World Records in 1953 as having the world’s highest tides. More recent research from the Makivvik Corporation, which represents the Inuit of Nunavik, has reaffirmed this claim with fresh measurements showing Leaf Basin’s tides exceed those of the Bay of Fundy. The debate continues in part because the Bay of Fundy is far more accessible and better studied, while Leaf Basin sits in a remote Arctic region with limited monitoring infrastructure.
Why These Two Locations Get Such Extreme Tides
Tides everywhere are driven by the gravitational pull of the moon and sun on Earth’s oceans. But the open ocean only produces modest tidal swings, typically a meter or two. What turns a moderate ocean tide into a 17-meter wall of water is the shape of the coastline and the physics of resonance.
The Bay of Fundy works like water sloshing in a bathtub. Every enclosed or semi-enclosed body of water has a natural resonant period: the time it takes a wave to travel from one end to the other and back. The Bay of Fundy and Gulf of Maine system has a resonant period of about 13.3 hours. The main lunar tide that drives most tidal activity worldwide cycles every 12.4 hours. Because those two numbers are so close, each incoming tide reinforces the one already sloshing inside the bay, amplifying the range dramatically over time.
On top of resonance, the bay’s funnel shape plays a critical role. NOAA identifies funnel-shaped bays as particularly effective at magnifying tidal height. As the tide pushes into the Bay of Fundy, the coastline narrows and the seafloor rises, forcing the same volume of water into a smaller and shallower space. The water has nowhere to go but up. Minas Basin, at the bay’s head, is connected by a channel only 4.5 kilometers wide, which acts as a bottleneck that concentrates tidal energy into an even smaller area.
Ungava Bay operates on similar principles. Its coastline funnels incoming tidal water from Hudson Strait into the progressively narrower Leaf Basin, and the basin’s geometry is close enough to tidal resonance to produce comparable amplification.
Other Notable High-Tide Locations
While eastern Canada dominates the extreme end of the scale, several other places around the world experience impressively large tides:
- Severn Estuary, UK: The funnel-shaped estuary between England and Wales produces tidal ranges up to 15 meters (49 feet), making it the highest in Europe. Its shape and shallow depth amplify tides from the Bristol Channel.
- Mont Saint-Michel, France: This iconic island monastery experiences tidal ranges up to 14 meters (46 feet), with the tide advancing rapidly across vast, flat mudflats.
- Turnagain Arm, Alaska: A narrow inlet near Anchorage sees tidal ranges around 12 meters (40 feet). The shallow, constricting channel creates a tidal bore, a visible wave that travels upstream as the tide comes in.
- King Sound, Australia: Located in Western Australia’s Kimberley region, this inlet produces tidal ranges of about 12 meters (39 feet), the largest in the Southern Hemisphere.
Every one of these locations shares the same basic ingredients: a funnel-shaped or narrowing coastline, relatively shallow water, and a geometry that happens to be close to resonance with the natural tidal cycle.
What Extreme Tides Look Like in Practice
If you visit the Bay of Fundy at low tide, you’ll see exposed ocean floor stretching hundreds of meters from the shoreline, with fishing boats sitting on mud and sand. Six hours later, those same boats are floating in 15 meters of water. The transformation is so dramatic that the region has become one of Canada’s top tourist attractions, with visitors walking the ocean floor at low tide and kayaking over the same spot hours later.
The speed of the tidal change creates real hazards. In areas with gently sloping shorelines, the incoming tide can advance horizontally faster than a person can walk, cutting off escape routes to higher ground. The tidal currents themselves are strong enough to make swimming or boating dangerous for anyone unfamiliar with the timing. Local tour operators time their excursions carefully, and tidal schedules are posted prominently throughout the region.
These extreme tides also make the Bay of Fundy one of the most studied sites for tidal energy generation. The sheer volume of water moving through narrow channels twice a day represents an enormous, predictable source of kinetic energy, with peak currents in Minas Channel averaging about 3.3 meters per second during ebb tide.