Final Fantasy XIV: Stormblood will bring two new character classes to the MMORPG, one of which is the Samurai. Final Fantasy 14's Samurai class will use the katana as their primary weapon and was announced at the Final Fantasy XIV FanFest keynote in Frankfurt, Germany.
Coming with the samurai class, Final Fantasy 14 will get a new continent to the east that will have a new player city named Kugane. Kugane will feature architecture that is reminiscent of Feudal Japan and is more than likely intended to be the homeland of the Samurai.
If you create a new character and choose to be a Samurai, you'll start at level 50. Samurai will share armor with the Monk class, so if you already have some of that hold onto it.
You can play as the Samurai class when Final Fantasy XIV: Stormblood releases on June 20, 2017. Also, keep in mind that when Stormblood releases that the PlayStation 3 version of FF14 will be discontinued, so if you haven't done so yet, you'll need to transition to the PC or PlayStation 4 version of the game before that date.