The only place I know where a stranger can play sport bridge in St.Petersburg is bridge club "Ligovski" (Tambovskaya ul. 63 = Тамбовская ул. 63). It is open only for pair tourniments:
In each event there are some people looking for a partner, so that a stranger can find a partner online. I evaluate the probability of finding a partner as 90%. Moreover, in most cases your partner will not be too stupid (most of the players are not worse than "advanced" in Bridge Base Online, some of them are much better).
English speaking people should not worry about language problems, most of the players can communicate in English (at least if you force them).
The club standard for bidding is a version of polish club which we call "Rubber Standard". The base of the system (alhtough with my own choice of the set of convections) can be found here. Most of all can bid a natural system with 5 card major openings like SAYC, some people can bid Precision.
In defence we use inverted signals (encourage and even - small) and italian discards (odd - strength, even - suit preference). Leading from AK most of all use the following old-fashion convenction:
If you have any questions do not hesitate to contact me , Victor Zimnitskiy (ZimnitskiyVA[at]airnet.ru), or Alexander Alekseev (ab48[at]mail.ru)