Longines Flagship

Most Longines Flagship references take a 18 mm watch strap: 31 of 120. The lug width follows the case size: 26 mm case → 13 mm, 30 mm case → 15 mm, 36 mm case → 18 mm and 39 mm case → 20 mm.

Shop 16 mm Shop 18 mm Shop 20 mm

Longines Flagship lug width by case size

120 references measured. Updated 2026-10-29.

Case	Lug width	References	Watch strap attachment	For example
20 mm	10 mm	3	—	L4.215.4.12.6, L4.215.4.52.6, L4.215.4.72.6
25 mm	13 mm	3	—	L4.216.4.12.6, L4.216.4.52.6, L4.216.4.72.6
26 mm	13 mm · 12 mm on 6 · 16 mm on 2	18	—	L4.274.3.07.7, L4.274.3.21.7, L4.274.3.22.7
30 mm	15 mm	18	—	L4.374.3.21.7, L4.374.3.27.7, L4.374.3.37.7
36 mm	18 mm · 20 mm on 2	33	—	L4.716.4.12.6, L4.774.0.57.6, L4.774.3.07.7
39 mm	20 mm	27	—	L4.803.3.22.7, L4.803.3.32.7, L4.803.3.37.7
40 mm	21 mm · 20 mm on 1	18	—	L4.984.3.21.7, L4.984.3.22.7, L4.984.3.27.7

References that take a different watch strap

L4.274.0.57.6: 12 mm, not the 13 mm of most 26 mm cases
L4.274.0.87.6: 12 mm, not the 13 mm of most 26 mm cases
L4.274.4.76.6: 16 mm, not the 13 mm of most 26 mm cases
L4.274.4.87.6: 16 mm, not the 13 mm of most 26 mm cases
L4.274.4.92.6: 12 mm, not the 13 mm of most 26 mm cases
L4.274.8.21.2: 12 mm, not the 13 mm of most 26 mm cases
L4.274.8.22.2: 12 mm, not the 13 mm of most 26 mm cases
L4.274.8.27.2: 12 mm, not the 13 mm of most 26 mm cases
L4.716.4.52.6: 20 mm, not the 18 mm of most 36 mm cases
L4.716.4.72.6: 20 mm, not the 18 mm of most 36 mm cases
L4.796.4.78.2: 20 mm, not the 21 mm of most 40 mm cases

Questions about the Longines Flagship

Do all Longines Flagship case sizes take the same watch strap?

No. The lug width changes with the case size: the 26 mm case takes 13 mm, the 30 mm case takes 15 mm, the 36 mm case takes 18 mm, the 39 mm case takes 20 mm and the 40 mm case takes 21 mm. Check your case diameter before you buy.

Can two Longines Flagship watches with a 26 mm case take different watch straps?

Yes. Of the 18 Longines Flagship references with a 26 mm case, 10 take 13 mm, 6 take 12 mm and 2 take 16 mm. The reference number decides, not the case size alone.