It depends where you are staying. There is a Mass at ten AM in the Cathedral. It is often bilingual. Also, there is a Mass in English at 11:30 at the Puerto Plata Village Hotel in the Playa Dorada. Tourists from the Playa Dorada and Costa Dorada can get to that fairly easily.
If you are staying in Costambar or Cofresi, there is a Mass in English there too, I think at eight thirty AM. I am not certain where that Mass is celebrated, however.
My experience with tour reps and hotel reception areas is that most do not know where or when the Mass in English is celebrated. We often have people arrive very early for Mass because they were told ten thirty or eleven in the Playa Dorada.
If you will be in Sos?a, there is a Mass there (San Antonio de Padua) at ten AM on Sundays. That Mass, I believe, is in English or is bilingual. Both priests of that parish speak enough English to be able to celebrate the Mass in it.
It is true, also, that if you have any background in Latin, the Mass in Spanish is easy enough to follow.