Type 212CD / 214 / 209

ThyssenKrupp Marine Systems (TKMS) is the world leader in conventional AIP submarines. Type 209 (the original class, 1970s+) is the most exported diesel-electric submarine ever — about 60 boats in 14 countries (Greece, Turkey, Argentina, Brazil, Chile, Colombia, Ecuador, Egypt, India, Indonesia, ROK, Peru, Venezuela, South Africa). Type 214 adds PEM fuel cells for AIP (2–3 weeks submerged without snorkelling) — Greece (4), ROK (9 as KSS-II Sohn Won-Il), Portugal (2), Turkey (6 in build-up locally). Type 212CD is the latest variant — 73 m, 2,700 tons, AIP, lithium-ion batteries — Norway + Germany jointly bought 6 boats in 2021–2025. Singapore Type 218SG (Invincible class) is a separate 218 derivative with X-rudder and Singapore specifications.