Are there nonstop flights from London (LCY) to Santorini (JTR)?

No. The fastest connection is via Zurich, about 4h 5m of total flying time.

What is the fastest connection from London (LCY) to Santorini (JTR)?

via Zurich ≈ 4h 5m, via Luxembourg ≈ 4h 5m, via Thessaloniki ≈ 4h 7m (estimated flying time, excluding layovers).

from 25,000 JAL miles (economy, one way, based on the published award charts).

London City Airport (LCY) to Santorini International Airport (JTR)・2,615 km

No nonstop flights. The fastest connection is via Zurich (ZRH), about 4h 5m of flying time (layover not included).

With milesJAL 25,000 miles+ (via MAD)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

11 one-stop options, sorted by estimated flying time. Tap one to see the airlines on each leg and booking links.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.