There was a vast armada of minesweepers that supported the D-Day landings. Of the 1213 ships involved in the landings, 287 were minesweepers; 24% of the total (though 32 of these ships were in reserve). These were divided into the larger 'fleet' minesweepers and the smaller 'coastal' minesweepers. These ships were supported by a considerable number of small craft - danlayers to mark cleared paths and motor launches to guide and support the minesweepers. Counting these vessels, a total of ~350 ships were involved in the minesweeping effort. Most of these ships were British, with just 22 American minesweepers taking part.

The main role of the minesweepers was to clear routes through the mine barrier the Germans had laid to protect the French coast. This was made considerably simpler by the fact that the Germans had left a clear channel parallel to the coast behind the mine barrier; this allowed them to move ships safely along the coast to carry supplies. This meant that waters close to the coast did not have to be cleared initially; instead, only the waters further from the coast had to be cleared. Similarly, the coastal waters of the UK were regularly swept, and so did not need special clearance.

The work of the minesweepers began in an area known as the 'Spout'. This was where the assault convoys, which had set off from ports along the south coast of the UK, congregated and turned south towards France. This had largely been cleared before the invasion began, but the waters that forces heading for Utah Beach had to travel to had not been routinely swept. These were partially swept by the British 14th and 16th Minesweeping flotillas on the 4th; this was a day early, as the invasion had originally been planned for the 5th, but was postponed a day due to bad weather. During this sweeping, the 14th located a small minefield, but did not have time to sweep it before the postponement signal was received. Allied commanders decided that this had been created by German small craft jettisoning mines mid-Channel, and was not a serious threat to the invasion. The route was not changed, and channels through the field were swept by both the 14th and 16th Flotillas on the 5th-6th. However, a loose mine from this field sank the American minesweeper Osprey.

Once the ships had passed through the 'spout', they had to pass through the German mine barrier. For each of the beaches, two narrow channels were swept through the minefield, with widths between 400m and 1,200m. One channel was for faster shipping, with a minimum speed of 12 knots, and the other was for slower ships, with a minimum speed of 5 knots. Each channel was swept by a single minesweeping flotilla of eight fleet sweepers, with a ninth in reserve. These flotillas were supported by four motor launches, which cleared the paths for the sweepers, two trawlers towing sweeps for magnetic mines, and four danlayers. There were twelve flotillas assigned to the operation, with ten clearing individual channels and two held in reserve. To ensure a maximum of surprise, the sweepers travelled close ahead of the assault convoys. The sweepers travelled at 7.5 knots, which meant that in the slower channels, the minesweepers had to backtrack for 40 minutes. This manoeuvre was carried out just before they entered the expected range of German coastal radar. Few mines were found, with a total of 31 being located in channels heading to Utah, Juno and Gold.

Once the routes through the mine barrier had been cleared, the minesweepers had three main jobs; clearing routes parallel to the coast for minesweeping ships, linking the channels through the barrier, and widening the channels. By this time, there was no need for secrecy, as the assault convoys were entirely within view of the coast. The ten flotillas were split up between these tasks. Three were assigned to clearing routes for the bombarding ships, three to sweeping lateral channels, and four to widening the channels through the barrier. The clearance of the bombardment routes was soon completed, as was the clearance of lateral routes between the channels for each beach. As these tasks completed, the flotillas joined their colleagues sweeping the main mine barrier.

The inshore waters, between the positions where the transports moored and the coast, were not swept. Doing so would call for more ships than the RN had available, the Germans were not expected to have laid mines there, and it would impose a delay that would remove any chance of surprise. Instead, these waters were swept after the assaults were carried out. To clear these waters, each beach was provided with two flotillas of coastal sweepers, and a group of six landing craft with sweeping equipment. These were equipped with specialist equipment for sweeping 'ground mines', which sat on the seabed unlike the classic 'moored' mine which floated above an anchor that held it in place. No mines were found by these flotillas on D-Day; mines only started to show up in the following days as the Germans reacted.

The minesweeping operation was generally successful. Only three ships would be definitely sunk by mines between the 5th and the 7th, with another possible. The first was the aforementioned Osprey. The next ship to hit a mine, doing so on the 6th, was the British destroyer Wrestler. She detonated a mine while trying to round up stragglers from a convoy of LSTs heading through Channel 7 to Juno Beach. She survived to struggle back to port, but the RN chose not to repair her; the mine had heavily damaged her, and she was an old ship (built 1918). Finally, the American transport Susan B Anthony was sunk while passing through the channel to Utah on the 7th, fortunately with no casualties aboard. The American destroyer USS Corry may have been sunk by a mine close to Utah Beach, but she was also under fire from a gun battery at St. Marcouf, and this has a better claim.