Gdynia   is a port city in northern Poland. Gdynia, together with nearby Gdańsk and Sopot are often referred as Tricity (pl: Trójmiasto). Gdynia was first mentioned in the 13th century as a fishing village. Its career began after World War I, when it became Poland´s main harbour and the big sea port at the Baltic Sea, which it still is.
Gdynia is one of the youngest and modern cities in Poland. In the early 1900s Gdynia was a little village, but after WW1 and establishing the Free City of Gdańsk, the Polish Government decided to build a deep-sea port. Construction began in 1921. The city rose fast in the 1920s and 1930s, so architecture and planning reflect European trends of the day - Modernism. The city continues to grow to this day. Today, Gdynia is a modern city with a population of a quarter-million and is the second major polish port in the Baltic Sea after Gdansk.
The nearest airport is in nearby Gdańsk Lech Wałęsa Airport IATA: GDN, 25 kilometers from the city center. Airport is a a popular destination for low-price flights from many European airports. Domestic flights are also available. Transfer bus  line 510 connects airport and Gdynia Central Station, but it runs only a few times a day.
The main railroad station is Gdynia Główna run by PKP . Gdynia is one of the biggest railway hubs in Poland with connections to Warsaw, Krakow, Poznan, Wroclaw, Katowice, Szczecin, Torun, Bialystok and many others. If traveling in the coastal area Gdansk, Sopot and Gdynia, then look out for the SKM commuter train. Travel from nearby Gdansk takes about 40 minutes (3.50 zl) with the frequent SKM  urban trains, which leave every 8-20 minutes.
From Gdansk by the route E75 just east along the coast.
Zarząd Komunikacji Miejskiej (ZKM)  operates buses and trolleybus. Network is efficient, and frequent. Locals are keen to help with directions but always ask several people and see if they agree.
Tickets for a bus:
Here's the key to understanding Gdynia bus and trolley-bus route numbers:
Szybka Kolej Miejska (SKM)  is fast regional commuter rail between Gdańsk - Sopot - Gdynia. It's fast and cheap. Ticket price depends on distance eg.
Tickets for a SKM train:
Gdynia is a relatively modern city and one will not find many historical buildings. The oldest building in Gdynia is 13th century St. Michael Archangel's Church in Oksywie. There is also a 17th century neo-Gothic manor house located in the Folwarczna Street in Orłowo. However, what most tourists look for Gdynia deals with its recent past. In the harbour there are two museum ships anchored, the ORP 0Błyskawica destroyer and the Dar Pomorza Tall Ship frigate. Gdynia is also famous for its numerous examples of early 20th century architecture, especially monumentalism and early functionalism. Recently reconstructed Świętojańska street and Kościuszki square are also worth mentioning. The surrounding hills and the coastline attract many nature lovers. Leisure pier and cliff-like coastline in Kępa Redłowska as well as the surrounding Reservation Park are also popular. 1.5 kilometres long promenade leads from the marina in the city centre to the beach in Redłowo. Most of Gdynia can be seen from Kamienna Góra (54 metres asl) or a newly built observation point near Chwaszczyno. You can also take hydrofoil or ship trip to Gdańsk Westerplatte, Hel or just see port.
Gdynia is the only city in Poland and one of the few in Europe to pride itself on such long and accessible seashore. You will easily catch great views of the sea, and also find long promenades, beautiful waterfronts, marinas, yacht clubs and great sand beaches.
Gdynia is a great place for shopping.
On the Hel Peninsula:
On the Vistuale Peninsula: