Arena Quests in Monster Hunter World can be started in the Gathering Hub of Astera. Talk to the NPC behind the counter there and he will offer you different Arena quests. More quests are unlocked as you progress in the game and slay more monsters out in the wild.
Arena matches let you fight monsters inside an arena with a predetermined set of armor and weapons to choose from. Your reward depends on how quickly you kill the monster. There are even global leaderboards to keep track of who killed it the fastest. Up to two players can take part in arena quests! It's the perfect way to compare how you stack up against other hunters.
What's good is that the monster cannot run away from you and you don't have to track it down. If you want to farm monster materials this is just the fastest way to get them plus you get vouchers for winning. The vouchers can be exchanged for free meals at the canteen. It's also a fun activity to do with 2 players.
The game features two trophies & achievements "Step into the Arena" and "Nowhere to Go but Up" for winning 1 and 50 arena matches respectively.
There are always a few weapons and armor sets to choose from before every match. You will also be given a specific set of healing items. So don't worry about bringing anything to the fight.