The modern attack submarine is capable of unleashing an accurate barrage of conventional or nuclear cruise missiles against land-based targets and surface while also having the facilities to counter enemy submarines. Additionally, submarines can be used to assist special forces and in clandestine intelligence gathering. Many modernized world navies utilize the submarine primarily as a deterrent in territorial waters.
For the purposes of the GFP final ranking, landlocked nations are NOT penalized for the lack of a standing naval force. However, nations with a standing navy ARE penalized for lack of certain naval assets. This GFP listing does not make a distinction between nuclear-powered and diesel-electric types nor does it take into account submarine type (attack, nuclear-capable, etc...), system age or construction/unit quality.
Submarines strength data through 2015.
Partial Sources: CIA.gov, CIA World Factbook, wikipedia.com, public domain print and media sources and user contributions. Some values may be estimated when official sources are lacking.