Hi

We are planning to take a cruise vacation to Mexico (Puerto Vallarta, Mazatlan, Cabo), my concern is with oil spill, are the beaches there affected from it.

Also first time going, are these ports safe?

No (those cities are not affected by the oil spill)
Yes (those ports are perfectly safe)

Wrong side of Mexico, you'll be fine. So far Mexico is completely fine I think, but the Pacific coast is unlikely to be impacted.

We are headed to Key West, FL in 3 weeks and the oil spill hasn't made it there yet, so I highly doubt it will make it to the Western side of Mexico, which is closer to California than the Gulf of Mexico.

I've gone to Mazatlan two years in a row and always felt perfectly safe. I traveled to PV a couple years ago and also felt safe there. Both towns have lots to do -- beaches, sightseeing, shopping, restaurants, etc. Sounds like a great cruise - enjoy!!

One thing I will suggest, is that in each of these cities, when you dock, get away from where the cruiseship terminal. This is never the nicest part of town, and is typically more expensive since they know the cruiseship passengers are coming in (taxis, restaurants, etc.)

Are you going to do activities arranged thru the cruiseline, or you want to plan your own days in each port?