Tokyo is on the exact same time as Seoul year-round (0 hours difference: KST UTC+9 in winter and KST UTC+9 in summer). When it is 9:00 AM in Seoul, it is 9:00 AM in Tokyo. Best meeting window: 9:00 AM – 5:00 PM KST in Seoul (9:00 AM – 5:00 PM JST in Tokyo — Golden 9–5 Overlap).
At the standard 0 hours offset (KST to JST), Seoul and Tokyo share 8 hours/day of simultaneous 9:00 AM – 5:00 PM business hours: 9:00 AM – 5:00 PM KST in Seoul equals 9:00 AM – 5:00 PM JST in Tokyo.
Both Seoul (KST) and Tokyo (JST) are simultaneously inside 9:00 AM – 5:00 PM core working hours (8h/day year-round).
Covers 10 hours/day when either Seoul (KST) or Tokyo (JST) is outside 7:00 AM – 9:00 PM local time.
Geographically, Seoul (South Korea, 37.57°N, 126.98°E, IATA: ICN) and Tokyo (Japan, 35.68°N, 139.65°E, IATA: HND/NRT) are separated by a great-circle distance of 1,149 km (714 miles, approximately 2h non-stop flight). By longitude, true solar time in Tokyo is 51 minutes ahead of Seoul (a 51-minute divergence from the 0 hours standard civil clock offset): Seoul (37.57°N, 126.98°E) sits 8.02° west of the 135.0°E KST reference meridian, so mean solar noon occurs at 12:32 PM KST year-round, while Tokyo (35.68°N, 139.65°E) sits 4.65° east of the 135.0°E JST reference meridian, so mean solar noon occurs at 11:41 AM JST year-round.
| Seoul Time | Tokyo (Standard (KST → JST)) | Day Shift | Call Status |
|---|---|---|---|
| 9:00 AM KST (Morning Start) | 9:00 AM JST | Same day | Working Overlap (9–5) |
| 12:00 PM KST (Midday / Noon) | 12:00 PM JST | Same day | Working Overlap (9–5) |
| 3:00 PM KST (Afternoon) | 3:00 PM JST | Same day | Working Overlap (9–5) |
| 6:00 PM KST (Evening Wrap-up) | 6:00 PM JST | Same day | Shoulder Hours |
| Seoul (KST) | Tokyo (Standard (KST → JST)) | Day (Tokyo) | Availability (Seoul ↔ Tokyo) |
|---|---|---|---|
| 12:00 AM KST in Seoul | 12:00 AM JST in Tokyo | Same day | Seoul–Tokyo Overnight |
| 1:00 AM KST in Seoul | 1:00 AM JST in Tokyo | Same day | Seoul–Tokyo Overnight |
| 2:00 AM KST in Seoul | 2:00 AM JST in Tokyo | Same day | Seoul–Tokyo Overnight |
| 3:00 AM KST in Seoul | 3:00 AM JST in Tokyo | Same day | Seoul–Tokyo Overnight |
| 4:00 AM KST in Seoul | 4:00 AM JST in Tokyo | Same day | Seoul–Tokyo Overnight |
| 5:00 AM KST in Seoul | 5:00 AM JST in Tokyo | Same day | Seoul–Tokyo Overnight |
| 6:00 AM KST in Seoul | 6:00 AM JST in Tokyo | Same day | Seoul–Tokyo Overnight |
| 7:00 AM KST in Seoul | 7:00 AM JST in Tokyo | Same day | Seoul–Tokyo Shoulder |
| 8:00 AM KST in Seoul | 8:00 AM JST in Tokyo | Same day | Seoul–Tokyo Shoulder |
| 9:00 AM KST in Seoul | 9:00 AM JST in Tokyo | Same day | Seoul–Tokyo 9–5 |
| 10:00 AM KST in Seoul | 10:00 AM JST in Tokyo | Same day | Seoul–Tokyo 9–5 |
| 11:00 AM KST in Seoul | 11:00 AM JST in Tokyo | Same day | Seoul–Tokyo 9–5 |
| 12:00 PM KST in Seoul | 12:00 PM JST in Tokyo | Same day | Seoul–Tokyo 9–5 |
| 1:00 PM KST in Seoul | 1:00 PM JST in Tokyo | Same day | Seoul–Tokyo 9–5 |
| 2:00 PM KST in Seoul | 2:00 PM JST in Tokyo | Same day | Seoul–Tokyo 9–5 |
| 3:00 PM KST in Seoul | 3:00 PM JST in Tokyo | Same day | Seoul–Tokyo 9–5 |
| 4:00 PM KST in Seoul | 4:00 PM JST in Tokyo | Same day | Seoul–Tokyo 9–5 |
| 5:00 PM KST in Seoul | 5:00 PM JST in Tokyo | Same day | Seoul–Tokyo Shoulder |
| 6:00 PM KST in Seoul | 6:00 PM JST in Tokyo | Same day | Seoul–Tokyo Shoulder |
| 7:00 PM KST in Seoul | 7:00 PM JST in Tokyo | Same day | Seoul–Tokyo Shoulder |
| 8:00 PM KST in Seoul | 8:00 PM JST in Tokyo | Same day | Seoul–Tokyo Shoulder |
| 9:00 PM KST in Seoul | 9:00 PM JST in Tokyo | Same day | Seoul–Tokyo Late evening / night |
| 10:00 PM KST in Seoul | 10:00 PM JST in Tokyo | Same day | Seoul–Tokyo Late evening / night |
| 11:00 PM KST in Seoul | 11:00 PM JST in Tokyo | Same day | Seoul–Tokyo Late evening / night |
Neither Seoul (KST, UTC+9, Asia/Seoul) nor Tokyo (JST, UTC+9, Asia/Tokyo) observes Daylight Saving Time. Across all 12 months, Tokyo remains 0 hours the same time as Seoul.
No Daylight Saving Time observed. Remains on KST (UTC+9) year-round.
No Daylight Saving Time observed. Remains on JST (UTC+9) year-round.
Seoul and Tokyo have a 0-hour time difference year-round, sharing KST (UTC+9) in winter and KST (UTC+9) in summer.
Yes — 4:00 PM KST in Seoul is 4:00 PM JST (same day) in Tokyo, which is inside standard 9:00 AM – 5:00 PM business hours in both cities.
Aim for 9:00 AM – 5:00 PM KST in Seoul, which is 9:00 AM – 5:00 PM JST in Tokyo (8h/day of 9–5 overlap). Avoid calling between 9:00 PM – 7:00 AM KST (+1 day) in Seoul (9:00 PM – 7:00 AM JST (+1 day) in Tokyo), when at least one city is outside 7:00 AM – 9:00 PM.
Neither Seoul (Asia/Seoul) nor Tokyo (Asia/Tokyo) observes Daylight Saving Time, so the 0 hours offset never changes.
Year-round under standard alignment, 9:00 AM in Seoul is 9:00 AM JST in Tokyo, and 12:00 PM (noon) in Seoul is 12:00 PM JST in Tokyo.