>>50659031Not at all. The first actual instance where the story lets you even visit a location that you'll need to visit later is after leaving Diglett's Tunnel. You can take Route 9 to reach Memorial Hill instead of going to Konikoni City, though of course nothing can actually happen until you do the story bits in the city.
The next time is once you're allowed to actually enter Malie City. Then you're allowed to visit Route 10 and/or 11 before speaking to Lillie at the library. Keep in mind that Route 10 and 11 are basically simplistic lines and it's not like you can continue on for any meaningful discovery until the story lets you, so it's pretty underwhelming.
There are optional areas. There's the easily-accessible first graveyard, which has a little story about a woman with a Machamp. There's Kala'e Bay that's apparently secret though the game makes sure to force you to walk almost up to its entrance so it's not like you're finding it. There's the Melemele Sea, a big open space of water accessible through Lapras later. Not particularly interesting. There's Ten Carat Hill which is kind of interesting? You can get Rockruff there, but this area is completely blocked off until after you finish the first Kahuna battle, so it makes it feel like an afterthought. You can go back with Lapras and Machamp to get a Z-Crystal I guess.
Let's compare the similar Union Cave in Johto. An NPC says he hears cries from deep within the cave on Fridays (hint). You can only access the depths of the cave after getting Surf, which is after the fourth Gym. If you go on Friday, you can find a wild overworld Lapras at the very bottom. The cave itself is more of a dungeon with more complex geography and Trainers. There are multiple exits, with some leading to new areas of the Ruins of Alph. From there, you can find wild Smeargle and Natu, as well as the final puzzles to unlock the rest of the Unown, which can be used to complete the Unown Pokédex.
