13-15 September 1950, to 06:30
Flying Fish Channel and the bombardment
Joint Task Force 7 — about 180 American and 60 allied ships under Vice Admiral Arthur Struble — closes on Inchon, a port with one of the greatest tidal ranges in the world: landing craft need about 23 feet of water to cross the mud flats, LSTs about 29, so there are two usable high tides on 15 September, at 06:59 and 19:19. On 13 and 14 September six destroyers anchor close off Wolmi-do, the fortified island guarding the harbor, to draw and silence its guns, while the cruisers Toledo, Rochester, Kenya and Jamaica fire from several miles south. Shore batteries hit Collett, Gurke and DeHaven on the 13th; Lt (jg) David Swenson is killed and eight sailors wounded. On the 14th the destroyers fire about 1,700 five-inch shells. In the night Lt Eugene Clark, landed earlier on an offshore island, switches on the navigation light on Palmi-do and the attack force feels its way up the narrow Flying Fish Channel. About 400 of Inchon's roughly 2,000 KPA defenders hold Wolmi-do. Bombardment resumes at 05:45.
15 September, 06:33 to noon
Green Beach: 3/5 takes Wolmi-do
Lt Col Robert Taplett's 3d Battalion, 5th Marines, grounds on Green Beach, a 200-yard strip on the island's north-west shore, at 06:33 — three minutes late — against light resistance. Company H clears North Point and climbs the northern nose of Radio Hill; Company G takes the southern half; ten tanks land at 06:46, among them the new M26 Pershings. At 06:55 Sgt Alvin Smith raises the flag on Radio Hill. Prisoners come out of caves near the causeway after a tank fires into them. About 10:00 Lt John Counselman's platoon, with tanks and after a napalm strike by Corsairs, crosses the narrow causeway to Sowolmi-do. Mopping up ends by noon. No Marines are killed; 17 are wounded. KPA losses on the islands are given as 108 killed and 136 captured by one account (Korean War Online); others are believed sealed in caves. Then the tide runs out, and 3/5 waits alone on the island through the afternoon.
15 September, 17:30
The evening tide: Red Beach and Blue Beach
After a second bombardment and rocket salvos from the LSMRs, the main landing comes in at 17:30 with only about two hours of daylight left. On Red Beach, north of the causeway in the city itself, the 5th Marines' 1st and 2d Battalions land abreast in LCVPs from Henrico and Cavalier and go over a high seawall with scaling ladders. On the left, Company A meets bunkers and trenches below Cemetery Hill; leading his 3d Platoon over the wall, 1st Lt Baldomero Lopez is hit while about to throw a grenade at a bunker, and smothers the grenade with his body to protect his men. He is awarded the Medal of Honor posthumously. Four miles to the south-east by water, the 1st Marines' 2d and 3d Battalions cross some 4,500 yards of flats in amphibian tractors to Blue Beach; smoke and darkness scatter some of the waves.
15-16 September, night
The beachhead by night
Cemetery Hill falls to Company A within minutes, by most accounts. The 5th Marines then fight up Observatory Hill — today's Jayu (Freedom) Park, where MacArthur's statue stands — the 1st Battalion taking its northern half and the 2d Battalion the southern half, the British Consulate and the edge of the tidal basin, along a line about 3,000 yards long. Eight LSTs ground on Red Beach at dusk under mortar and machine-gun fire; their return fire reportedly also strikes Marines on the hills. 3/5 crosses the causeway to rejoin its regiment, and the 1st ROK Marine Regiment comes ashore. By morning both regiments hold their first-day objectives, the 1st Marines on the high ground east of Blue Beach. Marine losses for 15 September: 20 killed, 1 died of wounds, 1 missing, 174 wounded.
16 September
East along the Seoul road
The ROK Marines clear Inchon while the two Marine regiments push east. At dawn six T-34 tanks, without infantry, come down the highway near Kansong-ni and are caught by eight Corsairs of VMF-214; Capt William Simpson is killed when his plane fails to pull out. About 11:00 Lt Col Harold Roise's 2/5 meets Lt Col Allan Sutter's 2/1 at Hill 117, and about 13:30 2/5, led by Lt Granville Sweet's five Pershings, enters Kansong-ni, where the tanks knock out three hidden T-34s. Puller's 1st Marines attack about 16:00 and tie in on the right; Taplett's 3/5 reaches the edge of Ascom City, the old Japanese arsenal at Bupyeong. At 18:00 Maj Gen Oliver P. Smith takes command ashore.
17 September
Tanks at dawn, and on to Kimpo
At dawn six more T-34s of the 42d Mechanized Regiment, with about 200 infantry of the 18th Division, drive west from Ascom City into 2/5's outposts. Lt Lee Howard's platoon of Company D holds the knoll above the road; Cpl Okey Douglas knocks out the first tank with a 2.36-inch rocket launcher, and Pershings, recoilless rifles and rockets — among them Pfc Walter Monegan of 2/1 — destroy the rest. MacArthur comes ashore that morning. Companies E and F clear Ascom City; 2/5 then turns north and by evening is at the southern end of Kimpo's main runway, each rifle company in its own perimeter, with 1/5 on its right. The 1st Marines grind along the highway toward Sosa.
17-18 September
Kimpo Airfield taken
Kimpo's defenders — a few hundred men of mixed units under a Chinese-trained brigadier general, Wan Yong by Marine accounts — counter-attack three times in the dark. About 03:00 Lt Edward Deptula's platoon of Company E beats off four assaults at its outpost; the other attacks are contained, and the survivors flee toward the Han. At dawn 2/5 sweeps the field and secures it by 10:00, for 4 killed and 19 wounded; a helicopter lands that morning and Marine Corsairs begin flying in from Japan the next day. On the highway, 3/1 takes burning Sosa and Hill 123, where North Korean mortars inflict about 30 casualties. The 7th Infantry Division begins landing at Inchon: the 32d Infantry is ashore on the 18th.
19 September
The 7th Division turns south
Before noon the 2d Battalion, 32d Infantry relieves 2/1 on the right flank south of the Seoul highway, and at 18:00 the zone passes to the 7th Infantry Division as the 31st Infantry lands. The Marines close on the Kalchon, the last stream before Yongdungpo and the Han: Company B, 5th Marines takes Hill 118, Ridge's 3/1 Lookout Hill, and Sutter's 2/1 advances nearly three miles behind its tanks. In the next days the 7th Division drives south through Anyang; its spearhead reaches Suwon on the night of 22 September and Suwon airfield is secured the next morning, and the 5th Marines cross the Han on 20 September for Seoul. By one count more than 125,000 North Korean prisoners fell into UN hands in the weeks after the landing (Britannica).