FIFA has approved the official name of the stadium on Krestovsky Island

The official FIFA site published a list of the names of the official stadiums that will be used during the 2018 World Cup. Seven matches, including the semi-finals and the third place play-off will takeplace at the Saint Petersburg stadium.
FIFA has approved the official name of the stadium on Krestovsky Island

Other arena received the following official titles:
Ekaterinburg Arena -Ekaterinburg
Fischt Stadium- Sochi
Kazan Arena - Kazan
Kaliningrad Stadium - Kaliningrad
Luzhniki Stadium - Moscow
Spartak Arena - Moscow
Mordovia Arena - Saransk
Stadium Nizhny Novgorod - Nizhny Novgorod
Rostov Arena -Rostov-on-Don
Samara Arena -Samara
Volgograd Arena - Volgograd

Progress on the building of Zenit's new stadium is given frequently on this website and information on the plans for 2018 are on fifa.com