The free trial, which kicks off today (March 11th, 2022) and goes through March 17th, is only available for Switch Online members — sorry, PC users. And for the duration of that week, you get access to “Monster Hunter Rise” in its entirety. Even the sometimes bizarre franchise crossover content.
For all intents and purposes you’ll be playing the full game for free, because that’s exactly what’s happening. You’ll be able to make your own character, complete missions for the main single-player campaign, take part in cooperative online hunts with friends and other players, and enjoy every other element the full game has to offer. The only catch is you’ll lose free access once the trial period is over.
With that said, all of your save data will remain even after the cutoff date, so if you like what you play enough to buy the full game you won’t have to worry about losing any of the progress you made during the trial. Then you can see how much you can accomplish before the “Sunbreak” expansion releases this summer, 2022.