# Distance from Kelso (KLS) to Sofia (SOF)

> 9,593 km · estimated flight time 12h · Ultra-long-haul route.

## Summary

- **Distance**: 9,593 km / 5,961 mi / 5,180 nm
- **Estimated flight time**: 12h
- **Heading**: 24° (north northeast)
- **Return heading**: 337° (north northwest)
- **Classification**: Ultra-long-haul
- **Type**: International (United States) → Bulgaria
- **Intercontinental**: North America → Europe
- **Time difference**: +10h (When it's 09:13 in Kelso, it's 19:13 in Sofia)
- **Elevation difference**: 1,722 ft (SOF is higher than KLS)

## Airports

### [Southwest Washington Regional Airport (KLS)](https://www.flightduration.online/airport/kls-kelso-southwest-washington-regional-airport/1ef266df-2607-6b02-a2f2-06bb2780ed98)

- City: Kelso, United States
- ICAO: KKLS
- Timezone: America/Los_Angeles
- Coordinates: 46.120000, -122.900000
- Elevation: 20 ft

### [Sofia Airport (SOF)](https://www.flightduration.online/airport/sof-sofia-sofia-airport/1ef266df-436b-611c-bff1-06bb2780ed98)

- City: Sofia, Bulgaria
- ICAO: LBSF
- Timezone: Europe/Sofia
- Coordinates: 42.700000, 23.410000
- Elevation: 1,742 ft

## Route notes

This is an ultra-long-haul route, one of the longest in aviation. It requires wide-body aircraft with extended range capability such as the Airbus A350-900ULR or Boeing 777-200LR. Passengers should prepare for an extended flight with multiple meal services.

Time-zone information: When it's 09:13 in Kelso, it's 19:13 in Sofia.
With a 10-hour time difference, expect significant jet lag.

## Related

- [Southwest Washington Regional Airport (KLS)](https://www.flightduration.online/airport/kls-kelso-southwest-washington-regional-airport/1ef266df-2607-6b02-a2f2-06bb2780ed98)
- [Sofia Airport (SOF)](https://www.flightduration.online/airport/sof-sofia-sofia-airport/1ef266df-436b-611c-bff1-06bb2780ed98)
- [Flight duration calculator](/#calculator)