Can I play Destiny 2 without PS Plus?

You can play Destiny 2 without PS Plus however most of the game modes and features will not be available.

You will be able to do:

• Story missions for the main Destiny 2 campaign and each of the DLC's you own.
• Planet activities such as Adventures, Patrols, Public Events & Lost Sectors but on your own, no other players will join you.

You will not be able to do the following:

• Strikes
• Raids
• Crucible PvP
• Gambit PvEvP
• Forges
• Reckoning
• Menagerie
• Vex Offensive
• Nightmare Hunts
• Join fireteams with other players

Even though you can do things like public events, these are designed to be completed by groups and will be difficult on your own.

The stuff you will not be able to do includes most of the late game content and IMO the real fun and rewarding part of playing Destiny 2.

My advice is that you need a PS Plus subscription to make Destiny 2 worthwhile.

Edit 1: Alternatively you can play on PC where online play is available without a subscription, however there is no cross play if your friends are on another platform and you will need a PC powerful enough to run it.

Edit 2: Destiny 2 New Light is now available for free so you can try out a lot of the content to help you decide.