Most people needing to reach Positano from Rome will take the train (Trenitalia or ITALO Treno) to Napoli Centrale, then the Circumvesuviana commuter train to Sorrento, then the SITA bus. Alternatively (April through October), they will take the train to Salerno, then the Cooperativa Sant'Andrea ferry boat direct to Positano.
This is the "conventional" solution for travel from Rome to Positano.
But there is a way to get to Positano without a single connection!
This solution is particularly useful for people with mobility problems, who may have difficulty lifting luggage on and off trains, or connecting from the train to the bus or ferry boat.
The solution is to take the DIRECT Marozzi bus from Rome's Tiburtina bus depot (300 meters from Rome's metro system and airport train to FCO Airport from Tiburtina Station).
This bus operates ONLY from June 1 through September 30. It departs daily at 7:00 a.m., arriving in Positano at 11:30. The bus stops in Sorrento en-route. The one-way fare is 21 Euros. Advance reservations are optional but not mandatory.
1. Direct service. No need to haul luggage from train to bus or train to ferry. No need to lift luggage on and off trains. Stow luggage in the underfloor baggage compartment of the bus.
2. Cheap: only 21 Euros, versus 22, 36 or 43 Euros on the Trenitalia train to Napoli Centrale, plus 4 Euros on the Circumvesuviana train to Sorrento (or 25, 39 or 46 Euros on the Trenitalia train to Salerno, plus 12 Euros on the ferry boat to Positano).
3. When factoring in the connection time in Naples or Salerno, the direct bus may be nearly as fast.
1. Slow: 4.5 hours, versus 3-4 hours by combination train/bus or train/ferry (NOT counting connection time in Naples/Sorrento or in Salerno). May be subject to traffic delays.
2. Seasonal: direct bus operates only from June through September.
3. Limited schedules: only at 7:00 a.m. (making connections from inbound flights at FCO airport impossible).
RETURN SERVICE: From Positano at 16:10, arriving Rome Tiburtina bus depot 21:00.