Another country to which fin manufacture is outsourced is Malaysia, which began with the rubber plantations it inherited from the British Empire and diversified into the production of rubber consumer goods. It has taken me several years to disentangle the country's web of rubber fin manufacturers. Here's what I have gleaned so far from my online searches:
Malaysian Manufacturer: Adila
Design used for Aqualine, Eyeline, Swim Stuff and Water Gear brands.
Malaysian Manufacturer: AFSCO
Design used for Aqualine, Aqualung Sport, Boltz, Sporti, Equina, Tritan, Hawaiian Reef Explorer, Madwave, Kiefer, Finis and many other brands.
Malaysian Manufacturer: CYH
Design used for Aqualine, Aqualung Sport, Atlantis, Deep See, Hawaiian Reef Explorer, Kiefer, Madwave and many other brands.
Malaysian Manufacturer: PWin
Design used for Beco, Head, Ocean, Eyeline, Vorgee and many other brands.
Note how the same brand names crop up for several different fin designs. In practice, this means that a western brand would opt for one design over a given period then replace it with another design to encourage their loyal consumers to replace their old fins with new ones.