I answered a question very, very similar to this one a while ago, so I'll just copy-paste that answer and change some of the irrelevant parts.

The depiction of Omaha Beach in Saving Private Ryan is reasonably realistic, although some concessions were made in the name of dramatic effect and practicality of filming. The "Omaha Beach" scene was actually filmed in Ireland instead of France. The film crew could not alter the beach very much, as it is a protected site and had to be returned to its original state after filming. This precluded some of the corrections listed below. Saving Private Ryan can be thought of as a sort of "alternate history" of D-Day, that begins with the Rangers' deviation of landing plan.

This view shows most of Dog Green sector and the beginnings of the cliffs that rise up and form the terrain of Charlie sector. Dog Green is on the left and middle; the beginnings of Charlie sector are off to the far right. Pointe du Hoc has even steeper cliffs, and is further still to the right, off the edge of the screen. Company C of the 2nd Ranger Battalion landed at Dog Green in the film. In reality, they landed at Dog Green, and then diverted to Charlie.

A closer view of the Dog One exit. The two bunkers of WN 72 can be seen at either end of the low concrete wall. They contained antitank guns, not machine guns. One of them had a 50 mm pedestal gun, the other one an 88 mm antitank gun. This photo is at high tide, with the water lapping up against the concrete sea wall. This modern sloped wall replaced the shingle and its low wooden wall. At low tide, several hundred yards of nearly flat beach would be exposed.

A cross section of a typical part of Omaha Beach. From examinations of photos, this analysis matches the period Dog Green sector quite well, although there are deviations.

And here's a map of the entirety of Omaha Beach for your convenience. In my description, I reference sectors of this map.

A list of goof-ups, both made for dramatic effect and practicality of filming:

1. The beach itself is too short; at low tide, the water is around 300 yards from the shore; the brief views from the bunkers make it seem like the water line and landing craft are right under their noses.

2. The beach obstacles in the movie are arranged in an almost haphazard way; the log ramps are even backwards! (their points should face inland; landing craft were to "ride" up the ramps during high or receding tides and either flip, or detonate the mine at the tip)

3. Task Force B (Company C of the 2nd Ranger Battalion and a platoon of DD tanks from Company B, 743rd Tank Battalion) could have used one of two plans on June 6th: A. Land at Dog Green sector beside (on the right flank from the Americans' point of view) Company A of the 116th RCT (29th Infantry Division) and follow them in their attack on Vierville, proceed on to attack a German strongpoint at Point et Raz de la Percee, then join up with other companies of the 2nd Ranger Battalion (Task Force A; Companies D, E, and F) at Pointe du Hoc. Or B:, land at Charlie sector, proceed directly up the cliffs, and attack the strongpoint at Point et Raz de la Percee directly. After that, they would meet up with Task Force A at Pointe du Hoc. In Saving Private Ryan, something vaguely resembling Plan A was used. In reality, C/2 landed, saw the severe beating that A/116 was taking at Dog Green and diverted, implementing Plan B instead.

4. There were no towering bunkers at Omaha Beach like in the film. The two most significant bunkers that existed in Dog Green sector that I've described in the photo of the Dog One exit above were small and actually faced sideways, not out to sea, to protect their apertures from naval gunfire and other attacks. Closer photos of the bunkers can be found here. They fired down the beach in enfilade, not out at the water. An observation post, concrete machine gun "tobruks" and mortar pits, and trenches of WN 71 and WN 73 were located further up on the flatter parts of the hill, and the top of the bluffs.

5. The Dog One (D-1) exit that the Rangers clear in the film is not correctly portrayed. Instead of being a narrow stepped footpath like in the film, it was in reality a paved road, blocked by a massive reinforced concrete obstacle. The film crew, as noted, could not damage the beach too much, which precluded the clearing of land in order to make the proper road for the scene. The 121st Engineer Combat Battalion of the 29th Infantry Division blew up this wall with ten cases of TNT around 3:00 PM. The Dog One exit was not assaulted from the beach, being surrounded via Vierville by troops that had moved up the bluffs.

6. The shingle, and wooden sea wall that topped it, are missing, replaced with the sand slope you see in the film. After the war, the concrete sea wall was put there. The shingle was extremely difficult for tanks to surmount, as it was made of small smooth stones or pebbles that the sea washed up; it was slippery and traction was very poor. It was removed by engineers with bulldozers after the beach landing. The sandy shelf that extends behind the sea wall to the bluffs is now built up with buildings and such. In WWII it was completely clear, planted with mines. It varied widely in its width, sometimes being quite close to the bluffs, other times about 100-200 yards away.

7. Company C of the 2nd Ranger Battalion is depicted in the film as being transported to Omaha Beach in LCM 3s from the USS Thomas Jefferson (APA-30); Company C, in reality, was transported by British Landing Craft Assault with British crews, from the HMS Prince Charles. Its likely this concession was made for practicality; presumably no running LCAs could be found.

LCA	Passengers	Fate
418	1st platoon and company commander	Sunk after landing
1038	2nd platoon

Eight (Reddit's formatting won't let me put "8") The Saving Private Ryan Rangers landed on Dog Green sector; the DD tanks of Company B of the 743rd Tank Battalion that were supposed to be there are nowhere to be found! The comment that Captain Miller makes about the armor "foundering in the Channel" is a tad inaccurate; the only tanks that were foundering were those of the 741st Tank Battalion on the other side of the beach, over 4 miles away! How could Miller know what was going on all the way down there? The tanks in Dog Green sector certainly didn't founder in the Channel. The 743rd Tank Battalion landed relatively unscathed. Company B of the 743rd Tank Battalion (16 M4A1 DD tanks) aimed for Dog Green and hit their target, 16 tanks being deposited directly onto the beach, although eight were destroyed literally within seconds, one of them being slammed in the side by an antitank round from one of the aforementioned bunkers as soon as it hit the water. Company C of the 743rd moved east from their landing point at Dog White sector to Dog Green, to help clear the Dog One exit. The tanks led a hard life, struggling to find targets and being easy pickings for German artillery, and being forced to move constantly due to the rising tide. A/743, unlike B/743 and C/743, did not have DD tanks, but rather 16 M4 or M4A1 Shermans equipped with wading trunks, and 8 with bulldozer blades. The 741st Tank Battalion landing with the 1st Infantry Division was organized the same way; Company A with wading tanks and tank dozers, and Companies B and C with DD tanks. The three DD tanks visible in photos taken by Robert Capa are thus the elusive three (the only three) from the 741st's B and C Companies that survived, being deposited directly on the beach at about 0640 after their canvas flotation skirts were torn by an explosion. All amphibious Shermans on D-Day, both American and British, were equipped with the T54E1 steel chevron track. The American DDs were late 1943 production Pressed Steel Car-manufactured M4A1s, the British DDs were M4A4s.

Strangely enough, a wading tank appears in this promotional image for the film.

741st Tank Battalion: Easy Red sector; three surviving tanks were deposited astride the border between Easy Red and Fox Green sectors

Battalion	Company	LCT (tanks)	Status
741	B	LCT-537 (4)	all sunk
741	B	LCT-599 (4)	all sunk
741	B	LCT-600 (4)	one tank sunk, three taken directly to beach
741	B	LCT-603 (4)	all sunk

Battalion	Company	LCT (tanks)	Status
741	C	LCT-549 (4)	all sunk
741	C	LCT-598 (4)	all sunk
741	C	LCT-601 (4)	all sunk
741	C	LCT-602 (4)	all sunk

Company B, 743rd Tank Battalion: Dog Green sector

Battalion	Company	LCT (tanks)	Status
743	B	LCT-535 (4)	landed on beach
743	B	LCT-586 (4)	landed on beach
743	B	LCT-587 (4)	landed on beach
743	B	LCT-589 (4)	landed on beach

Company C, 743rd Tank Battalion: Dog White sector; moved west to Dog Green sector to assist B/743 and A/116 in clearing the D-1 exit

Battalion	Company	LCT (tanks)	Status
743	C	LCT-588 (4)	landed on beach
743	C	LCT-590 (4)	landed on beach
743	C	LCT-591 (4)	landed on beach
743	C	LCT-713 (4)	landed on beach