Tasman to Iron Pot (River Derwent)

A spectacular 22.5km swim down Timtumili Minanya/ River Derwent, starting at the Tasman Bridge in Hobart to the historic Iron Pot lighthouse at the mouth of the estuary.

DISTANCE

22.5km

WATER TYPE

River / Estuary

EXPERIENCE

Intermediate

LOCATION

Hobart

REGION

Hobart & South

Swim Stats

First completed: February 2022 (Rod Watkins, Australia)

Successful swims: 10 (9 have been ratified)

Fastest male: 5:48:00 (Rod Watkins, December 2024, Tandem Swim)

Fastest female: 5:48:00 (Samantha Poulsen, December 2024, Tandem Swim)

See the Honour Roll below

Overview

The Tasman Bridge to Iron Pot swim is one of Tasmania's most distinctive marathon swims, following Timtumili Minanya/ River Derwent from the heart of Hobart towards the river mouth and the open waters of Storm Bay.

Starting beneath the Tasman Bridge, swimmers head downstream along the Derwent, passing a constantly changing landscape as the urban waterfront gives way to the wider river and its surrounding hills.

As the swim progresses, the character of the water changes again. The river broadens and the surrounding landscape opens out, with the historic Iron Pot lighthouse providing a distinctive and rewarding landmark for the finish.

At 22.5km, this swim provides a great stepping stone for those looking to increase their marathon swimming distance, before potentially tackling the Derwent River Big Swim.

Or for those who may have already completed the longer swim, the Tasman to Iron Pot swim offers a different perspective on the river, with water temperatures typically colder than upstream and more exposure to Tasmania's challenging winds.

Route Description

The swim starts beneath the Tasman Bridge. The most direct route is to stay closer to the western shore until the John Garrow Light at Sandy Bay, before tracking south-east towards South Arm. This does, however, mean crossing the shipping lane, so care must be taken here.

Swims can also track down the eastern shore of the Derwent, avoiding the shipping lane, which adds approximately 500 metres to the overall swim distance.

Once past the point at Cape Direction, it's approximately 900 metres to reach the Iron Pot lighthouse. There is only one safe exit point onto the rocks, on the northern side. If conditions allow, swimmers can exit the water here, clearing the water line to complete the swim. However, if conditions are not safe, swimmers should touch the rock at the lighthouse to mark the finish before swimming back to the boat.

See map below or click here to view in Maps.

What you should know

Swims will typically start around high tide, with approximately 6-7 hours of outgoing tide providing assistance to the swimmer.
While this is the Derwent River, the swim is in the lower parts of the estuary and therefore salt water.
Almost - if not all - of the swim will be in daylight hours.
The water temperature in December will be around 15C, around 16-17C in January and March, and likely to reach 18C in February.
During the summer months, winds tend to pick up from mid-morning, either from the south-west or south-east, so be prepared to head into these for the latter part of the swim.
Depending on the wind forecast, your pilot may recommend that you switch to the Tasman to Bruny swim instead, to get more shelter from any strong winds. The swim is a similar distance.

Before you go

Pilots must notify MAST of the planned swim route at least 48 hours in advance due to restrictions on swimming at the Tasman Bridge.
Your pilot will typically meet you at one of the marinas or boat ramps close to the city (e.g. Rosny boat ramp, Prince of Wales marina, Regatta Grounds boat ramp). From there, you will have a short boat trip to the Tasman Bridge where you will jump in to start the swim.
Your pilot will take you back to the pick-up point, as there are few places to get off the boat downstream of the city.

Honour Roll

Swim #	Name	Date	Time	Country	Route	Category	Type	Notes	Ratified By
1	Rod Watkins	12/02/2022	6:51:55	Australia	Tasman-Iron Pot	Unassisted	Solo	First recorded swim	DRBS
2	Brenda Norman	27/01/2023	6:30:00	Australia	Tasman-Iron Pot	Unassisted	Solo	First recorded female	DRBS
3	Tara Grout	06/02/2024	8:03:15	Australia	Tasman-Iron Pot	Unassisted	Tandem		DRBS
4	Julie Boxsell	06/02/2024	8:03:15	Australia	Tasman-Iron Pot	Unassisted	Tandem		DRBS
5	Sam Poulsen	26/12/2024	5:48:00	Australia	Tasman-Iron Pot	Unassisted	Tandem		DRBS
6	Rod Watkins	26/12/2024	5:48:00	Australia	Tasman-Iron Pot	Unassisted	Tandem		DRBS
7	Carolyn Anderson	29/01/2025	6:51:29	Australia	Tasman-Iron Pot	Unassisted	Solo		DRBS
8	Alyssa Seckinger-Crow	02/01/2026		Australia	Tasman-Iron Pot	Unassisted	Solo		Not ratified
9	Helen Conway	02/01/2026	7:09:56	Australia	Tasman-Iron Pot	Unassisted	Solo		DRBS
10	Debbie Lewry	10/02/2026	7:53:50	New Zealand	Tasman-Iron Pot	Unassisted	Solo		DRBS