The colonnade of St Isaac’s Cathedral is open to the general public and is accessible throughout the day for an entrance fee. In the morning the colonnaded opens at 10:30 and stays open till 22:30 in the evening (or till 4:30 during the White Nights). Note that both the cathedral and the colonnade are closed on Wednesday. From the observation deck you can basically see all of St Petersburg in every direction as you walk around. The only drawback is the crowds that gather most every day, so it may not be a place to escape the hustle and bustle of the streets, but the view is still spectacular.
The bell tower of the Peter and Paul Cathedral is the perfect location to see the opposite side of the Neva River, including the Hermitage, St Isaac’s Cathedral, the Admiralty and the Palace Bridge. The bell tower is open only in the summer (from May 1 to September 30) everyday except for Wednesday. During the winter months access is only available upon special request.
Etagi is a cultural centre with art exhibitions, a cafe and a space for various events. On the fifth floor of the building there is a artificially greened rooftop that is sometimes hosts events, such as music concerts, but most of the time is just open for visitors. There is no entrance fee and the roof is open 24 hours a day.
This rooftop is located in a slightly more residential part of St Petersburg, but not far away from Nevsky Avenue. The house you are looking for is located behind the Subway sandwich shop on the street. Enter the door to the right in the archway. If the door is locked, wait for somebody to come out and wander in. To find the rooftop access you need to get to the top of the stairwell and find the door that opens up onto the roof. From up there a view onto the area known as the ‘Five Corners’ opens up, a beautiful crossroad in the heart of St Petersburg.
A hidden rooftop that gives a gorgeous view onto the Neva River and Troitsky and Liteiny Bridges. This one is a bit of challenge to find. When at the address, you will need to enter into the arch on the right. When inside the front entrance to the building you will need to go up a spiral staircase up to the attic, the exit onto the roof is located at the top.
This rooftop has the most adventurous journey to find it. When at the address you will need to go inside the neighbouring courtyard. In the courtyard there is a fire escape that leads up onto to the roof. The whole journey up can take up to 30 minutes, but the view is rewarding : a panorama of Vosstaniya Square and some parts of Nevsky Avenue.
If tackling an unkept rooftop on your own seems like to risky an adventure, there are many locals that would happily guide visitors to the top and then return them smoothly back to safety. Although many locals offer this service, not all have guides that can speak English. This rooftop tour operator has received positive feedback and offers tours in English, but there are others out there easily located through a quick browser search. Make sure to listen to your guides and follow their instructions carefully.