Hel was defended by IVth battalion of KOP (Korpus Ochrony Pogranicza - Border Protection Corps) with 28 officers and 1 169 soldiers, under command of mjr Jan Wisniewski. The battalion was equipped with four 75 mm artillery guns, 6 excellent anti-tank 37 mm guns, nine 46 mm grenade thrower and two 81 mm mortars. The first defensive trenches were placed near Wielka Wies, second near Chalupy, and final line near Kuznice, where also big minefield was placed.
The last line of defence were two lines of pill-boxes near Jastarnia. The safety of the Hel peninsula were guarding three coastal batteries (XXXIst, XXXIInd, XXXIIIrd and later newly formed XXXIVth), which were forming the Command of the Coastal Artillery, also three counter landing batteries (41, 42 and 43). From air bombing Hel was defended by 2nd MDAP (Morski Dyon Artylerii Przeciwlotniczej - Command of the Naval Anti Aircraft Artillery), containing four AA batteries - 21st, 22nd, 23rd and 24th.
First batteries on Hel, were installed during years 1933-1934 when the "Greek" and "Danish" (XXXIInd and XXXIIIrd respectively) batteries were built. Third one named for lt Heliodor Laskowski, was installed during years 1934-1936. The XXXIst was consisting of 4 single turret 152 mm Bofors guns (range around 26 600 m), the XXXIInd and XXXIIIrd were equipped with 2 old 105 mm guns each. All of the counter landing batteries were built in June 1939, and had two obsolete 75 mm guns each.
2nd MDAP was formed on 1.IX.1935, but back then it was consisting only from the 21st, 22nd and 23rd batteries, which were equipped with Schneider 75 mm AA guns (model 1922). The 24th battery, was formed later in July 1939, and had eight brilliant 40 mm AA Bofors guns (two guns per platoon). The AA defence was also strengthen by 12 MG placed in the Hel harbours. The plans were made to built the airfield (near the Hel harbour, between the 24th battery platoons), where the squadron of the fighters could be based. The commander of the Hel Fortified Area was capt Wlodzimierz Stayer.
40 mm Bofors AA gun