Moskovsky Ave., 22, Saint Petersburg, Russia, 190013
The first address of Dostoevsky in St. Petersburg was Bolshoy Tsarskoselsky Prospect, the house of Collegiate Councillor Fyodor Dmitrievich Serapin, No. 7. The modern address is Moskovsky Prospect, No. 22. In a draft petition addressed to the monarch, M.A. Dostoevsky, who brought his elder sons Mikhail and Fyodor to Petersburg to enroll in the Main Engineering School, indicated his "temporary residence near Obukhov Bridge in a hotel at No. (text unfinished)." The researcher of Dostoevsky's work, Fedorov, suggested that the hotel where the Dostoevskys "could have stayed 'near Obukhov Bridge'" was the "stagecoach hotel in the 'huge' Serapin house, where 'order and cleanliness, arrangement and cheapness (as the newspaper 'Severnaya Pchela' wrote) are worthy of attention'." This information is repeated by another researcher, Belov, but he adds one important nuance. "Where did the Dostoevskys stay?" asks the researcher. And he answers: "...it was the 'Neapol' hotel by the Fontanka, on Tsarskoselsky (Obukhov) Prospect, No. 7...". For Belov, this seems to be no problem. However, in Fedorov's study, this is not the case. From the 1837 address book, it is known that there really was a hotel "Neapol" in Petersburg, also located "near Obukhov Bridge." However, there is no data to confirm that this was the name of the Serapin hotel specifically. Apparently, Fedorov tended to believe that the "Serapin" and "Neapol" were two different hotels, giving preference in the list of Dostoevsky's Petersburg addresses to the former. However, the researcher's argumentation seems shaky, even somewhat artificial. In the cited petition, M.A. Dostoevsky wrote that he settled in a hotel "near Obukhov Bridge." Fedorov insists that this indication corresponds only to the Serapin hotel, since "Neapol" was located not "at," but "beyond Obukhov Bridge," that is, on the other side of the Fontanka. In Nistrem's directory about the "Neapol" hotel, it is unequivocally stated: "near Obukhov Bridge." And how is the address of the Serapin hotel indicated? Surprisingly, it is not even mentioned here. And this is despite the fact that in another reference publication of the era, albeit somewhat later, the Serapin hotel is characterized as one of the best in the northern capital. "Regarding the arrangement of hotels for visitors to the capital, the proprietors cannot boast," wrote Pushkarev in 1841. "At least the following can be called decent hotels: in the Serapin house near Obukhov Bridge, Kulon’s, on Mikhailovskaya Square, Demut’s, on Bolshaya Konyushennaya, London, opposite the Admiralty — and only those."

However, the absence of the Serapin hotel in Nistrem’s directory (which lists 38 capital hotels) can be interpreted to mean that it is actually the "Neapol" hotel, but registered not by the surname of the homeowner (or owner), as most others were, but by a sonorous proper name (similar to the "London" and "Paris" hotels listed there). In that case, Belov is correct in placing the Dostoevskys not just in a hotel "near Obukhov Bridge," but specifically in the "Neapol" hotel. However, based on the sources available today, this remains only a research hypothesis that has not received documentary confirmation.
Sources:
Tikhomirov Boris Nikolaevich: ADDRESSES OF DOSTOEVSKY IN PETERSBURG: A CRITICAL ANALYSIS OF SOURCES AND EXPERTISE OF LOCAL HISTORY PUBLICATIONS
Fontanka River Embankment, 2, Saint Petersburg, Russia, 191187
Ligovsky Ave., 65, Saint Petersburg, Russia, 191040
Karavannaya St., 16, Saint Petersburg, Russia, 191023
Grafsky Lane, 10, Saint Petersburg, Russia, 191002
Kuznechny Lane, 5/2, Saint Petersburg, Russia, 191002
Rubinstein St, 32, Saint Petersburg, Russia, 191002
Kazan Street, 2, Saint Petersburg, Russia, 191186
Bolshoy Prospekt Vasilievsky Island, 4a, Saint Petersburg, Russia, 199034
6 Voznesensky Ave, Saint Petersburg, Russia, 190000
Bolshaya Podyacheskaya St., 5, Saint Petersburg, Russia, 190068
Nevsky Ave., 18, Saint Petersburg, Russia, 191186
Territory. Peter and Paul Fortress, 14, Saint Petersburg, Russia, 197198
Pushkinskaya, Saint Petersburg, Russia, 191180
3rd Krasnoarmeyskaya St., 8b, Saint Petersburg, Russia, 190005
litera A, Kaznacheyskaya St., 4/16, Saint Petersburg, Russia, 190031
Malaya Podyacheskaya St., 2, Saint Petersburg, Russia, 190068
Stolyarny Lane, 16, Saint Petersburg, Russia, 190031
27 Voznesensky Ave., Saint Petersburg, Russia, 190068
Bolshaya Konyushennaya St., 27, Saint Petersburg, Russia, 191186
3 Rimsky-Korsakov Avenue, Saint Petersburg, Russia, 190068
Serpukhovskaya St., 11, Saint Petersburg, Russia, 190013
3rd Krasnoarmeyskaya St., 11, Saint Petersburg, Russia, 190005
per. Ulyany Gromovoy, 8, apt. 36, Saint Petersburg, Russia, 191036
Sadovaya St., 37A, Saint Petersburg, Russia, 190031
Dostoevsky St., 2/5, Saint Petersburg, Russia, 191002
Grazhdanskaya St., 19/5, Saint Petersburg, Russia, 190031
Griboedov Canal Embankment, 104d, Saint Petersburg, Russia, 190068
Tikhvin Cemetery, Alexander Nevsky Square, 1, Saint Petersburg, Russia, 191167
Gorokhovaya St., 41, Saint Petersburg, Russia, 190031
Mikhailovskaya St., 1/7, Saint Petersburg, Russia, 191186