Books like the expanse?

Project Hail Mary by Andy Weir. Just finished the audiobook and thought it was fantastic. It could be technical at times like The Martian, but I find that stuff interesting.

Both fantastic books but I'm not sure they're Expanse-like. Definitely would recommend them. Skip the moon one, Artemis?
- I wouldn't say skip it altogether, I liked it a decent bit. Just not NEARLY on the same level as the other two for sure.
- I liked Artemis more than I thought I would have, but yeah, it's weaker than The Martian or Project Hail Mary.
I’m starting to put more Weir books on my list. I really love the way he writes. The Weir Easter egg in the Expanse was great.

Revelation Space series by Alastair Reynolds

I asked a similar question right after I finished The Expanse and the response I received was to read Revelation Space. Needless to say I wasn't disappointed!

I'm working on The Culture series by Ian Banks now.
- Second for culture, I'm really enjoying it!
Funny you should say that, I just recently started reading and it's fascinating. Alastair knows his shit.
- I really appreciate that he stuck to his guns on the self imposed “no FTL” rule for those books. It really makes things interesting
Seconded. Fantastic series with vast world building. Reynolds is a master class author

The foundation series by Asimov has a lot of similarities to both of those sagas in tone and content.

Red rising is great sci-fi, but it's more enders game(although a little more hardcore action).

I'm going to let this rattle around, I feel like there's something else I'm not remembering right off the bat.

Oh I guess not quite the same, but when anyone asks for a recommendation in sci-fi, I always say "the mote in God's eye" by Jerry pournelle and Larry niven

Not as large a scale as those books, but a fascinating story told in a unique and scientific way.

Excellent suggestion! The Mote in God's Eye is a classic. I really love the whole "...and on the gripping hand, as the Moties would say..." phrasing that came from that book :D
- Yeah the alien race was just so real to me the first time I read it, not particularly in how their society was structured, or their biology or anything else, but just how that world was relayed to the reader made that universe so much more real to me than many other first contact stories.
  
  How rapidly everyone felt like friends.

The Old Man's War series, and The Interdependency trilogy by John Scalzi.

Old man's war is quite fun. If I remember correctly it starts by doing the whole Full Metal Jacket bit where the first book is half boot camp then half war time. So it's familiar in feel yet funa and original in content.

While not super familiar with the expanse, I was extremely impressed with the "Enderverse" series. Both the Ender saga and accompanying Shadows saga build an amazing universe with rich lore and extremely humane characters.

In all honesty, "Enders Game" that started the series is probably the simplest and least interesting of all the books that followed.

Read them for the first time at the age of 45 and could not stop till I reached the recent final entry.

When I read Enders Game, no one told me what to expect, so I was thoroughly surprised by where it went. Highly recommend it to people if they don’t know enough to ruin the story.

There's a bunch of books similar to The Expanse, but not all of them live up to what makes _The Expanse great, the hard science, but here's some that I'd suggest to itch that Space Opera itch you're having trouble scratching:

Vatta's War
Honor Harrington
Children of Time (I haven't read it yet but always hear how great it is.)
Star Carrier series
Heritage Trilogy
Commonwealth Saga
Foreigner Series
Dune
The Lost Fleet Series
Star Wars Expanded Universe
Star Trek Novels
Battletech/Mechwarrior series
Warhammer
Halo Novels
Clone Series
Old Man's War
Frontline Series
Foundation series

I've got so many others, I'll update a little more as I remember authors or titles.

Here's a pretty good list of stuff I definitely missed

I'll throw in my 2 cents. Children of time is a good trilogy, especially if you like biology but the 1st book was the best with each following book being weaker than the last. Definitely worth reading though as it scratches that hard sci-fi itch.

I'd also add the Remembrance of Earth's Past trilogy to this list, it's the only series that almost matches The Expanse in terms of pure greatness IMO. I read them a few months ago and I find myself thinking about the concepts and ideas introduced in the trilogy every few days still. Absolutely amazing books that any sci-fi fan should try. I will say that the characters are for the most part, pretty boring and don't come anywhere near the greatness of The Expanse's characters. It's the main complaint I see about those books are the fairly dull characters. The ideas and concepts the trilogy introduces are absolutely fascinating though, even better than anything from The Expanse IMO and it easily makes up for the lackluster characters. It's also fairly hard sci-fi like The Expanse and relies a fair bit on semi-realistic (for the most part) science like The Expanse does. Beware that these books have a fairly pessimistic view of the universe, but that's also what helps make the books so good.

I've gone back to The Three Body Problem multiple times since my first read just so I can re-read my favorite scenes from the book and those books almost single handedly reignited my love for space. I can't recommend them enough.
- OP mentioned TBP in the post so I left it off, also I just haven't read it yet, but definitely have to soon.
  
  Children of Time is probably the next sci-fi series I'm reading.

I've watched but not read Expanse. My first thought was Dune, I really enjoyed that.

The faded sun trilogy by C.J. Cherryh https://en.wikipedia.org/wiki/The_Faded_Sun_Trilogy

Also the Imperial Radch books by Ann Leckie are very good.

I second the Larry Niven suggestion. Good stuff

Stephen Baxter wrote the Xeelee Sequence. There are quite a few books to read, and it encompasses the entire history of the universe. Lot’s of amazing science within the realm of nonfiction, assuming life were simply more prolific.

I absolutely loved the Salvation Sequence by Peter F. Hamilton for the action and the refreshing unexpected twists and turns.

I second the Children of Time series as well for the "realistic-enough" world building, and Project Hail Mary.

Try Commonwealth Saga by Hamilton. It's three doorstoppers long and author sometimes excessive with descriptions, but, as space operas goes, it's magnificent.

If you want fun politics and war in the entire solar system, I recommend Red Rising and the the subsequent 2 novels (I haven’t read beyond that). The characters are incredibly sentimental but it was really fun to read. It doesn’t start off anything like The Expanse but politics within the entire solar system and divisions between the outer planets and asteroid belt were reminiscent of some scenarios.

If you want a more philosophical and hard science exploration of Humanity expanding beyond our solar system, dealing with long term evolution and exploring sentience in other species, I like Children of Time and the followup books.

Neither are very similar to Expanse but both series are great.

To add to the list, Seveneves.

I really enjoyed the Black Fleet Saga by Joshua Dalzelle.

I've only read his Omega Force and Marine books (they're not great literature by any means, but definitely a guilty pleasure for mindless, campy sci-fi action). I'll have to check out Black Fleet as I'm about to wrap up the final Cosmere book and want some good sci-fi for a change of pace.

Luna series by Ian MacDonald. Luna:New Moon, Luna : Wolf Moon, and Luna: Moon Rising. These books are set in the near future. Family clans have control of most of the Moon's resources. The books do a great job of showing the new society.

I haven't read The Expanse yet, just watched it, but you might enjoy the Spinward Fringe series by Randolph Lalonde. The first book is free too :)