The easiest way to visit the Panama Canal is to head to the Miraflores Visitors Center, just outside Panama City. This modern center features a four-floor interactive museum that looks at the canal's history, operations, expansion and ecology, an instructive 15-minute film and several viewing platforms, including the main one on the 4th floor with panoramic views of canal transits (the best times are from 9am to 11am and from 3pm to 5pm when transits are more frequent).
There is a direct bus to the Miraflores Visitors Center from the Albrook Bus Terminal in Panama City, but it is infrequent. Otherwise take a Paraíso or Gamboa bus from the terminal. These pass along the canal-side highway to Gamboa and will let you off at the ‘Miraflores Locks’ sign (US$0.35) on the highway, 12km from the city center. It’s about a 15-minute walk along the main road to the locks from the sign. You can also take a taxi; drivers will typically wait 30 minutes at the locks and then drive you back to the capital. Expect to pay no more than US$30 round trip, but agree on the price beforehand.