Gdynia in the mid-war period was the biggest Polish naval base, so the forces which were guarding the harbour were the biggest. The land defence forces were based in four mayor regions: Redlowo (South of Gdynia), Wejcherowo (West of Reda), Kartuzy (Southern West of Redlowo) and of course Gdynia. The major part of the defence forces were two Marine Rifles Regiments, both consisting of two battalions (1st - total of 58 officers and 1 850 soldiers, 2nd - total of 65 officers and 2 000 soldiers).

The third mayor force was MBON (Morska Brygada Obrony Narodowej - Naval National Defense Brigade), which was formed from five battalions, giving total number of approximately 120 officers and 2 800 soldiers. 1st MPS (Morski Pulk Strzelcow - Marine Rifles Regiment) was raised in 1931 while 2nd MPS and MBON in 1937. Other forces, smaller ones were: 1st Reserve Battalion (23 officers and 750 sailors), 2nd Reserve Battalion (with 23 officers and 754 soldiers), 3rd Reserve Battalion (with 25 officers and 750 soldiers, which formally was independent unit, but in fact was operating as III Battalion of 2MPS), Sappers Battalion, Liaison Platoon (4 officers and 320 soldiers) and National Police Platoon (around 650 soldiers). This units were equipped with eight obsolete 75 mm AA guns, 17 excellent 37 mm anti-tank guns, eighteen 46 grenade throwers, sixteen 81 mm mortars and 192 MG. The land artillery was gathered in Command of the Artillery under command of mjr Wladyslaw Kanski.

One of the "Canet" 100 mm guns
Because of the lack of trucks, units were constantly placed in Kepa Oksywska. Command of the Naval Artillery was divideded into three batteries: Ist Land Artillery Battery, which was the strongest of the three batteries, because it had four ex Russian 105 mm guns, IInd Land Artillery Battery had four 75 mm guns while IIIrd Land Artillery Battery had only three 75 mm guns. The problem was not only the age of the guns but also lack of ammunition. The numbers of the Command of the Artillery were 16 officers and 284 soldiers. The last two Artillery platoons were: 1st Positionary Artillery Platoon (which was operatingng within 2nd MPS) and 2nd Railway Artillery Platoon both with two 75 mm guns.

37 mm Bofors anti-tank gun
From sea Gdynia was defended only by XIth coastal battery (called Canet), built in 1930, and consisting of 2 old 100 mm guns (model 1891 - sic!), under command of mjr Stanislaw Jablonski. The air protection was assuring 1st MDAP consisting of four batteries (1st, 2nd, 3rd and 4th AA battery), built in the years 1930-1933. Each battery was consisting of two obsolete 75 mm AA guns. Also there were some miscellaneousus AA guns in the naval harbour and six 47 mm AA guns from ORP Baltyk. In September 1939 Polish ground forces were stationed in three sections: "Wejcherowo" where 1st MPS and Vth Battalion of MBON were stationed, "Kartuzy" where IInd and IVth Battalions of MBON were stationed, "Redlowo" where 2nd MPS and IIIrd Battalion of MBON were stationed. The rest of the forces had their camps in the suburbians of Gdynia.