Port Phillip Bay is a large, open coastal bay located in Victoria, Australia, serving as the gateway to Melbourne's port. It is a popular destination for sea kayaking, offering expansive views of the Melbourne cityscape and magnificent coastlines. The bay's waters are crystal blue, providing a stark contrast to the silty Yarra River that flows into it. For paddlers, key access points include dedicated boat launch ramps, such as the three-lane ramp at Boat Launch Ramp No. 3, and public kayak launch facilities at locations like Anderson Reserve and Clark Reserve. Sandringham Harbour is highlighted as a particularly safe and sheltered location to launch and land, as it provides a lee from winds in most conditions.

The paddling experience is heavily governed by weather and sea conditions, making careful planning essential. Wind is the primary factor, with paddlers advised to avoid winds blowing at 15 knots or more unless they possess advanced sea kayaking skills. Understanding fetch and lee is critical due to the bay's large, open exposure. Tidal currents are a significant consideration, and paddlers should consult tide charts for locations like Sandringham. A major hazard is The Rip, the narrow entrance to the bay from Bass Strait, which should not be crossed by kayakers. The bay can experience strong conditions that have led to rescues, such as paddle boarders being swept long distances. The water is used by a high volume of boat traffic, given it is Australia's busiest port area.

Wildlife sightings can include dolphins on the horizon. The bay contains sanctuary zones, such as Ticonderoga Bay, where paddling is permitted. The best season for paddling is summer, when waters are warmer. Facilities for paddlers include beach amenities, restaurants, and kayak rental services available at various points. A notable and challenging route is the "Across the Bay in a Day" trip, which is designed for experienced sea kayakers and is not suitable for beginners.