The Helsinki City Marathon and 17km Helsinki Street Run taking place on Saturday 12 August will cause major diversions to public transport. 
Helsinki City Marathon course
The event will affect traffic in particular in Etu- and Taka-Töölö, Meilahti, Ruoholahti, Länsisatama and Lauttasaari. Mäntymäentie will be closed to traffic around the Olympic Stadium from Friday 11 August 12noon to Saturday 12 August 9pm. At the start of the race, there may be delays to routes 2X, 7X, 58, 59, 69 and 848 on Nordenskiöldinkatu from 3pm to 3.15pm.
Streets and stops to be closed
Töölö and Meilahti: Mäntymäentie 11 August 6pm–12 August 9pm
Nordenskiöldinkatu/Reijolankatu at the start of the race on 12 August 3pm-3.15pm
Helsinginkatu 4pm-9pm
Töölönlahdenkatu 4pm-9pm
Lauttasaari: Tallbergin puistotie 3pm-8pm
Meripuistotie 3pm-8pm
Katajaharju intersection to Länsiväylä 3pm-8pm
Ruoholahti and Länsisatama: Hietalahdenranta 3pm-8pm
Ruoholahdenranta 3pm-8pm
Hietalahdenkatu 3pm-8pm
Merisatamanranta 4pm-8pm
Ehrenströmintie 4pm-8pm
Laivasillankatu 4pm-8pm
Puistokatu 4pm-8pm
Merikatu 4pm-8pm
Diversions to tram services
Tram routes will be mainly diverted on Saturday 12 August 3pm-9pm. The trams will serve all stops along the diversion routes. Tram routes 2, 3, 6T and 8 will be diverted, as well as tram routes 4 and 10, which are affected by track works. “Länsilinkki” (tram stops 0820 and 0821) will be closed 3pm-6.30pm.
Tram routes 2 and 3 will be diverted in three phases from 2.30pm to 9pm.
Phase 1: 2.30pm-4pm
Route of tram 2: Urheilutalo–Opera–Runeberginkatu–Kamppi–Central Railway Station.
Route of tram 3: Central Railway Station–Hakaniemi–Kallio–Urheilutalo.
The trams will switch route numbers at the Central Railway Station and Urheilutalo. See map
Phase 2: 4pm-7pm
Route of tram 2: Opera–Runeberginkatu–Kamppi–Central Railway Station.
Route of tram 3: Central Railway Station–Hakaniemi–Kallio–Läntinen Brahenkatu–Sturenkatu–Paavalin kirkko (St. Paul’s Church).
The trams will switch route numbers at the Central Railway Station. See map
Phase 3: 7pm-9pm
Tram 2 will run from the Opera to the Olympia Terminal as usual.
Tram 3 will run as usual until Kaarlenkatu. The northern terminus will be at St. Paul’s Church and the tram will not serve Helsinginkatu.
The trams will switch route numbers at the Olympia Terminal. See map
Eirassa raitioliikennettä korvaa In Eira, tram services will be replaced by bus 3X running from Lasipalatsi via Bulevardi and Fredrikinkatu to Neitsytpolku approximately 2pm-7.15pm. Passengers can change from tram to bus at the “Lasipalatsi” stop (H1902). On Mannerheimintie, bus 3X will use bus stops, otherwise it will use tram stops. See the route of tram replacement bus 3X
Other tram routes:
Tram 6T will run to the West Terminal using the route of tram 9 via Kamppi 3.30pm-7pm. The tram will not serve Mannerheimintie, Bulevardi and Hietalahti.
Tram 8 will run from Arabianranta along Hämeentie, Sturenkatu and Läntinen Brahenkatu to Sörnäinen (M) and continue along Hämeentie to Arabianranta 4pm-9pm. Katso Diversion route of tram 8
Tram routes 4 and 10 will be affected by track works.
Tram 4 will run only between Katajanokka and the Opera on Saturday. Replacement bus 4X will run to Munkkiniemi along Runeberginkatu,Topeliuksenkatu and Haartmaninkatu, from where it will continue along the route of tram 4 to the terminus in Munkkiniemi. In the direction of Töölö, the bus will use the route of tram 4.
Tram 10 will run only between Kirurgi and the Opera on Saturday. Replacement bus 10X will run to Pikku Huopalahti along Runeberginkatu, Topeliuksenkatu, Mannerheimintie and Vihdintie to the terminus in Korppaanmäki. In the direction of Töölö, the bus will use the route of tram 10. On Korppaanmäentie, the bus will serve tram stops.
Diversions to bus services
Bus services to/from Elielinaukio:
Töölönlahdenkatu will be closed to traffic 4pm-9pm and buses will run to Elielinaukio via Mannerheimitie, Postikatu and Asema-aukio. From Elielinaukio, buses will run via Postikuja and Mannerheiminaukio to Mannerheimintie. There will be staff directing traffic.
Buses to/from Lauttasaari:
Buses running via Lauttasaari will run in both directions to/from Länsiväylä via the Lemissaari intersection 3pm-8pm. The Katajaharju intersection will be closed to traffic and the “Lahnalahdentie” (1045 and 1046) and “Katajaharju” (1066 and 1067) bus stops will not be served.
Bus 20X will terminate at the “Melkonkuja” (1051) bus stop on Itälahdenkatu. The bus will use the route of bus 21BX … Lauttasaarentie–Särkiniementie– Wavulinintie–Heikkiläntie-Melkonkatu-Nahkahousuntie-Vattuniementie-Melkonkuja-Itälahdenkatu. The bus will not serve the bus stops between Lauttasaari Church and Katajaharju. Diversion route of bus 20X
Bus 21V will use the same route as bus 20X in Lauttasaari 3pm-8.30pm. Diversion route of bus 21V
Other bus routes:
Bus 14 will use the following route 3.30pm-6.30pm: Laivurinkatu–Tehtaankatu–Raatimiehenkatu–Pietarinkatu-Kapteeninkatu–Tehtaankatu–Laivurinkatu. The terminus will be at the “Neitsytpolku” stop. The bus will not serve the following stops: “Tehtaanpuisto” (1179 and 1180), “Perämiehenkatu (0444 and 0445), “Hernesaarenkatu” (1187 and 1188), “Munkkisaarenkatu (1185 and 1186), “Matalasalmenkuja (1189 and 1190), “Henry Fordin katu (1191 and 1192), “Pihlajasaarenkatu (1193 and 1194 and “Hernesaaren laituri” (1195 and 1196). Diversion route of bus 14
Bus 18 will run along … Laivurinkatu – Pietarinkatu – Kapteeninkatu – Tehtaankatu – Laivurinkatu – normal route 3.30pm-6.30pm.
The bus will not serve the “Eiran sairaala” (H1175), “Eira” (H1177 and H1178) bus stops. The terminus will be at “Eiran sairaala” (H1176). Diversion route of bus 18
Bus 24 will run along Korkeavuorenkatu, Tehtaankatu, Laivurinkatu, Pietarinkatu and Kapteeninkatu 3.30pm-6.30pm.
The bus will not serve the “Kapteeninpuistikko” (1206), “Meritori” (1208), “Merikatu” (1209) and “Neitsytpolku” (1207) bus stops. The terminus will be at “Kapteeninpuistikko” (1205). Diversion route of bus 24
Bus 70T will run via Nordenskiöldinkatu when Helsinginkatu is closed to traffic.
The services from Kamppi 3.36pm-8.41pm will run along Fredrikinkatu, Arkadiankatu, Runeberginkatu, Topeliuksenkatu, Nordenskiöldinkatu, Savonkatu, Aleksis Kiven katu and Sturenkatu.
The services from Suutarila 3.13pm-8.36pm will run along Sturenkatu, Aleksis Kiven katu, Savonkatu, Nordenskiöldinkatu, Topeliuksenkatu and Runeberginkatu. Diversion route of bus 70T
From Latokaski to Kamppi, bus 195 will not serve the “Munkkiniemen aukio” bus stop (1406) 3pm-4.30pm. The bus will run from Ramsaynranto to Paciuksenkatu. The bus will serve the “Munkkiniemen aukio” stop (1500). Munkkiniemen aukio” (1500). Diversion route of bus 195
Bus 502: Mäntymäentie will be closed to traffic from Friday 11 August 6pm.
Until the closure of Helsinginkatu on 12 August about 4pm, the bus will use the following route: Normal route - Helsinginkatu – Runeberginkatu – Ruusulankatu – normal route. The bus will not serve the “Töölön kisahalli” (2064 and 2065) bus stops. Diversion route of bus 502 via Töölö
On Saturday 12 August about 4pm-9pm, the bus will run via the Central Railway Station as Helsinginkatu will be closed to traffic.
The services from Merihaka 3.55pm-8.25pm will run via Hakaniemen ranta, Siltasaarenkatu, Kaisaniemenkatu, Vilhonkatu, Mikonkatu, Kaivokatu, Mannerheimintie, Arkadiankatu, Runeberginkatu and Topeliuksenkatu.
The services from Leppävaara station 3.35pm-8.35pm will run along Topeliuksenkatu, Runeberginkatu, Arkadiankatu, Mannerheimintie, Postikatu, Kaivokatu, Kaisaniemenkatu, Siltasaarenkatu, Hakaniemen ranta, Sörnäisten rantatie and Haapaniemenkatu.
The following stops will not be served: “Kallion virastotalo” (0226, 0253 and 2129), “Castréninkatu (0227 and 0228), “Kuntatalo” (0229 and 2128), “Wallininkatu” (2126 and 2127), “Diakoniapuisto” (2066 and 2067), “Töölön kisahalli” (2064 and 2065) and “Ratikkamuseo” (1328 and 1329). Diversion route of bus 502 via the Central Railway Station
On route 640, the services from Kamppi at 6.15pm and 8.05pm as well as the services from Maantiekylä at 3.37pm and 6.58pm will run along Mannerheimintie, Nordenkiöldikatu, Savonkatu, Aleksis Kiven katu and Sturenkatu. The “Ooppera (2026 and 2185), “Diakoniapuisto (2066 and 2067) and “Porvoonkatu (2122 and 2145) stops will not be served. Diversion route of buses 640 and 70T