Suzuka is located about 50 kilometers south of Nagoya, from where it can be accessed by JR or Kintetsu Railways. Alternatively, it can be accessed by Kintetsu Railways from Osaka.
How to get from Nagoya to the Suzuka Circuit (how to get to Nagoya)
By JR and Ise Tetsudo
The closest railway station to the race circuit is Suzuka Circuit Ino Station, a 20 minute walk from the circuit.
The one way journey from Nagoya Station to Suzuka Circuit Ino Station takes 60-90 minutes, costs 1060 yen and requires one transfer of trains at Suzuka Station (if you ride a Toba bound rapid train from Nagoya) or Yokkaichi Station (if you ride a Kameyama or Yokkaichi bound local train from Nagoya).
Over the grand prix weekend, special direct limited express trains named "Suzuka Grand Prix" operate between Nagoya Station and Suzuka Circuit Ino Station, taking just under one hour and costing about 2500 yen one way. Seat reservations are mandatory on these trains.
Note that the Japan Rail Pass covers only part of the journey, since the section between Kawarada and Suzuka Circuit Ino Station is owned by a non-JR railway company. The supplement fee to be paid by pass holders is 300 yen one way (650 yen in case of a limited express train).
By Kintetsu Railways
An alternative approach to the circuit is provided by Kintetsu Railways. The closest station, Shiroko Station, is a 20 minute bus ride from the circuit (390 yen one way).
The one way journey from Nagoya Station to Shiroko Station takes 40 minutes and costs 1720 yen by limited express train (tokkyu) or 50 minutes and 820 yen by express train (kyuko). Kintetsu trains are covered by the Kintetsu Rail Pass, but not by the Japan Rail Pass.
How to get from Osaka to the Suzuka Circuit (how to get to Osaka)
By Kintetsu Railways
There are two limited express train connections per hour from Osaka-Namba Station to Shiroko Station (100 minutes, 3120 yen one way, covered by the Kintetsu Rail Pass). One is direct, while the other requires a transfer at Tsu Station along the way. Seat reservations are mandatory. From Shiroko Station, it is a 20 minute bus ride to the circuit (390 yen one way).
The train journey from Osaka-Namba to Shiroko Station can also be done by slower express trains, in which case the one way fare is only 1800 yen, but the trip takes about 2.5 hours and usually requires two transfers along the way.