The followings are listed price
You can get special offers and/or choose the best rate on various hotel reservation sites such as hotels.com, hotelclub.com, tvtrip.com, cheaphotel.com, travel.com, hotelwide.com etc.

Hotels near COEX and rates  ( Unit : KRW )
 

category	name of hotels	# of rooms	distance to COEX	rack rate
5 star (★★★★★)	COEX InterContinental	651	venue hotel	310,000
	Grand InterContinental	530	annex building	330,000
	Park Hyatt Seoul	185	5 min on foot	410,000
	Hotel Lotte World	469	15~20 min by car	310,000
	Renaissance Seoul	493	5~10 min by car	312,000
	Imperial Palace	430	15~20 min by car	300,000
	The Ritz-Carlton Seoul	410	15~20 min by car	321,000
	JW Marriott Seoul	497	20 min by car	328,000
	Sheraton Grand Walkerhill Seoul	589	30 min by car	305,000
	W Seoul Walkerhill	252	30 min by car	375,000
	Lotte Hotel Seoul	1,124	45 min by car	320,000
	Millennium Seoul Hilton	681	50~60 min by car	420,000
	Seoul Plaza Hotel	455	45~50 min by car	280,000
	The Shilla Seoul	462	40~45 min by car	330,000
	Sofitel Ambassador Seoul	409	30 min by car	380,800
	The Westin Chosun Seoul	453	40~40 min by car	380,000
	Grand Hilton Seoul	396	more than 1 hour	300,000
	Mayfield Hotel	202	more than 1 hour	281,600
4 star (★★★★☆)	Novotel Ambassador Gangnam, Seoul	335	15~20 min by car	297,000
	Ellui Hotel	139	10~15 min by car	160,000
	Hotel Rivera	316	10~15 min by car	208,000
	Ramada Seoul	214	5~10 min by car	240,000
	Hotel Prima Seoul	120	10~15 min by car	156,000
	Bestwestern Premier Gang Nam Hotel	128	10~15 min by car	128,000
	Seoul Palace Hotel	283	5~10 min by car	200,000
	Seoul Kyoyuk Munhwa Hoekwan	252	20~25 min by car	140,000
	Hotel Capital	287	15~20 min by car	180,000
	Ramada Hotel & Suite Central	304	20~25 min by car	300,000
	Pacific Hotel	135	20~25 min by car	160,000
	Bestwestern Premier Hotel Kukdo	295	15~20 min by car	180,000
	Hotel President	303	20~25 min by car	140,000
	Seoul Koreana Hotel	344	25~30 min by car	172,000
	Seoul Sejong Hotel	273	20~25 min by car	250,000
	Seoul Royal Hotel	307	20~25 min by car	120,000
	Novotel Ambassador Doksan, Seoul	230	35~40 min by car	198,000
	Holiday Inn Seoul Seongbuk Seoul	128	20~25 min by car	184,000
	Lexington Hotel	232	40 min by car	219,000
	Bestwestern Premier Seoul Garden Hotel	362	25~30 min by car	170,000
	Bestwestern Niagara Hotel	101	25~30 min by car	160,000
3 star (★★★☆☆)	Ibis Ambassador Seoul	317	15~20 min on foot	105,000
	Samjung	163	10 min by car	148,000
	YOUNG DONG HOTEL	131	15 min by car	125,000
	GREEN GRASS HOTEL	76	5 min by car	100,000
	HOTEL SUNSHINE	110	10 min by car	100,000
	Hotel POPGREEN	69	20 min by car	104,000
	Hotel BluePearl	80	2~3 min by car	170,000
	Tria Hotel	48	10 min by car	90,000
	Hotel CALIFORNIA	101	15 min by car	110,000
	HOTEL LAKE	94	10 min by car	210,000
	HOTEL CENTRO	94	15 min by car	120,000
	HANKANG HOTEL	116	15~20 min by car	99,000
	HOTEL DONG SEOUL	101	15 min by car	100,000
	HOTEL Newkukje	142	30 min by car	135,000
	BEST WESTERN NEWSEOUL HOTEL	145	30 min by car	126,000
	HOTEL REX	93	25~30 min by car	117,000
	HOTEL PJ	221	30~35 min by car	105,000
	METRO HOTEL	90	30~35 min by car	68,000
	SAVOY HOTEL	103	25~30 min by car	99,000
	HOTEL PRINCE SEOUL	100	30 min by car	130,000
	ASTORIA HOTEL	94	30 min by car	120,000
	Hotel Ibis	280	40~45 min by car	109,000
	Hamilton Hotel	155	40~45 min by car	90,000
	HOTEL CROWN	197	40~45 min by car	131,769
	Hotel Crown Insadong	90	50 min by car	121,000
	HOTEL SEOKYO	115	30~35 min by car	180,000
residence	Oakwood	280	annex building	420,000
	Casaville Samsung Residence	130	10~15 min on foot	85,000
	Residence Seoul	130	10~15 min on foot	93,000