Keflavik International Airport is a Level 3 (SCR) airport. See IATA Worldwide Scheduling Guidelines.

Coordination address for SCR format message

E-mail: scr@airportcoordination.com
The Coordination office is open weekdays from 08:00 – 16:00 UTC.
Phone: +354 425 6060
E-Mail: bjarni.borgarsson@isavia.is

How to create SCR messages
http://airportcoordination.com/index.asp?DocumentID=765

Information for Military Operators
All military flights operating to and from Keflavik are required to have a Handling Agent before arrival.
The Handling Agent will make arrangement for fuel service, hotel accommodation, and inform of flight arrival and departure.

Requirements for military operators
Submit itinerary to Airport Coordination including aircraft type, tail number and handling agent.
Declare any explosives or hazardous items carried onboard as that information will affect parking assignment.