On 23 May 1964, line 24 acquired an expansion, numbered 28, consisting of a branching from ulica Bosmańska in Obłuże through Oksywie to the loop by Dowództwo Marynarki Wojennej. There were two types of trolleybuses on this line. The first type, indicated by a regular number 28, ran from ulica Śmidowicza through ulica Arciszewskich to Oksywie and returned via ulica Bosmańska. The second type, indicated by a 28 with a green strikethrough, ran the opposite direction, through ulica Bosmańska to Oksywie, returning via ulica Arciszewskich. These lines were one-directional, so a passing loop was established in Oksywie. The line 24 loop was moved to near the Gdynia Port Oksywie railway station.