Seiko SRPH31K1 5 Sports “Flieger” Blue Nylon Band Watch

Seiko SRPH31 Flieger

The 5 Sports line keeps finding new ways to interpret classic watch styles, and the SRPH31 goes after the German Flieger tradition. Pilot watches from the 1930s and 40s had specific requirements—high contrast dials, sword hands, no-nonsense legibility—and this watch respects those origins while staying firmly in modern territory.

The Flieger Formula

That blue sunray dial catches light the way a proper pilot watch should—readable in any conditions. The sword hands and Arabic numerals are directly descended from Type A observation watches. At 39.4mm, it wears closer to vintage pilot watch proportions than most modern reinterpretations.

The 4R36 Workhorse

Inside is Seiko’s reliable 4R36 automatic—24 jewels, 41-hour power reserve, hacking and hand-winding. It’s proven across the entire 5 Sports range and beyond. The exhibition caseback shows off the movement, though pilot watch purists might prefer a solid back.

Field-Ready Details

The blue nylon strap with orange lining adds character without being gimmicky. 100 meters of water resistance means it handles real life. Hardlex crystal protects the dial. LumiBrite on the hands and indices ensures the Flieger’s legibility tradition continues after dark.

Who It’s For

The SRPH31 works for anyone drawn to pilot watch aesthetics but wanting something more accessible than the usual suspects. The 5 Sports price point delivers serious value for a watch with this much design heritage behind it.