Definitely Osaka. It has a very lively center, some great museums, great food, shops and clubs. And it has Osaka castle (you see in every Samurai movie and movie on medieval Japan) and a great aquarium. Kobe is nice but not as nearly as interesting as Osaka.

Choosing between Osaka and Kobe in 2026 depends on your preferred "vibe" and travel goals. Osaka is the better choice for the majority of travelers; it is known as "Japan’s Kitchen" and offers unparalleled street food (Dotonbori), vibrant nightlife, and world-class shopping. It also serves as a more central transport hub, making it easier to take day trips to Kyoto and Nara. Kobe, on the other hand, offers a more relaxed, upscale, and compact environment. It is famous for its namesake beef, its historic "Ijinkan" foreign residences, and a beautiful harbor front with a mountainous backdrop. Stay in Kobe if you prefer a quieter, more romantic atmosphere or are specifically interested in the local sake breweries and hot springs (Arima Onsen). However, since the two cities are only about 20 to 30 minutes apart by train, most people choose to base themselves in the high-energy environment of Osaka and visit Kobe for a pleasant afternoon or evening of dining and sightseeing.