From Osaka (Umeda/Osaka Station)
Take the Hanshin Main Line from Hanshin Umeda Station to Koshien Station. It's just 12-15 minutes and costs about ¥280. Trains run every few minutes. Koshien Station is a 3-minute walk to the stadium. This is the easiest and most popular route.
From Osaka (Namba)
Take the Osaka Metro Midosuji Line from Namba to Umeda (5 min), then transfer to the Hanshin Main Line to Koshien (15 min). Total time: about 25 minutes. Alternatively, take the Hanshin Namba Line directly — some trains go all the way to Koshien without transfer.
From Kyoto
Option 1: JR Special Rapid from Kyoto to Osaka (30 min), then Hanshin Line to Koshien (15 min). Total: about 50 minutes. Option 2: Hankyu Railway from Kawaramachi/Karasuma to Juso, transfer to Hanshin Line. Similar time but slightly cheaper.
From Nara
Take the Kintetsu Nara Line to Osaka-Namba (35 min), then Hanshin Namba Line toward Koshien. Total time: about 55-60 minutes. Direct trains are available on the Hanshin Namba Line.