Before I get started, I just want to let everyone know this is my first build and I apologize for the text heavy guide. I appreciate any comments and criticism and will do my best to read through the comments. Also, I am by no means an expert to this game, and not everyone will approve of this build.

This is a tank build and while you will be that backbone of your team, you generally won't have too many kills. Try to think of yourself as an assist king!

Now that the disclaimer is out of the way we can move on!
This is a very short, sweet and to-the-point build.
I am assuming you can read what his abilities do and that you are just here for items.
I'm not going to evaluate every in-game scenario against every champion.
I'm not showing any math, or any of that craziness (like I said, I'm no expert).
I'm simply giving you a view into a fun tanky champion that can do a little bit of damage and turn the tides of the game.

These runes could be transferred to pretty much any AP champions and be helpful. I don't think that you need to go out and pick up a whole new set of runes to play Nautilus. Magic Pen/Armor/Magic Resist will provide you with enough damage to be more than annoying, but will also give you the fun tankyness.

Why flat Armor/Magic Resist?
Nautilus is a melee champion, beyond that, he is a fairly SLOW, melee champion, who is easily harassed. The flat runes will help you stay in lane longer in the beginning of the game. At the end of the game, you can make up for the difference with your awesome tank items!

Why movement speed Quint?
Like I said before, these are good on practically every champion. If you prefer something else, then use what you prefer, this is a guide, not a law :P

I see a lot of different mastery trees, this is just what I enjoy to play with. I see a lot of people skip over Vigor, with the items I tend to build this talents helps a lot more than most people give it credit for. If you prefer Evasion, go for it, the 3 points switch over quite nicely. Just don't forget, Nautilus has a shield. Maybe I give the shield too much credit, but that's just me.
(Again, I am NO expert. If you have any suggestions I would love to hear them)

All of Nautilus' abilities are versatile! It's one of the main reasons that I enjoy playing him so much.
Take your first point in Dredge Line for the beginning game fight and leave in until the end.
Then grab Titan's Wrath, then Riptide. Max Titan's Wrath first. Since you are a tank, this move is AMAZING! Extra health and extra damage, whats not to love!?
(Don't forget to pick up your ultimate at 6, 11, and 16 of course!)

The items above are strictly a guide and are NOT to be followed every single game! They are the items I build the most often, but not in every case. If every enemy champ is AD then you would want to build a Thornmail rather quickly, for an entire AP team, Force of Nature.

I expect a lot of flak for not putting warmogs earlier in the build, I can accept that. I build these items because I enjoy the CDR and the Regen that comes from the items
No matter what team you are going against, grab a regrowth pendant and health pot at the beginning. As a tank, I don't get many kills, as a melee I am harassed off creeps in the beginning a lot. That's why I build into Philo Stone and grab a heart of gold for the gold generated, the health from the heart is great, and it's a prereq anyway. The order for the Spirit Visage and Wardens isn't very important. Make the call in game. Shurelya's I feel is very underrated. Make use of the activate, whether it's chasing, returning to lane, or running away, its on a 60 seconds CD, USE USE USE! Also for Randuin's, USE USE USE! Once you have randuin's you are pretty free to make your own choices, of course Warmogs is great, so is banshee's, but at this point in the game, you need to make sure you are grabbing items based on whats going on in the game, not in this guide.

I'm sure I will get all people trolling me about summoner spells. I'm showing you what I play with. You are a tank, heal is GREAT for tanks, its also great if you are new to the game. It makes the game a little more forgiving of your mistakes (and yes, I still make A LOT of mistakes).
For your other summoner spell, take what matches your play style. If you find yourself basing more often then maybe you should pick up Teleport. If you want to try to be a super support at the beginning make this Clarity or Clairvoyance, neither are as effective end game, but hey its all up to you and what you like to play with.

• Nautilus' passive is very impressive, try to harass your opponent with this by hitting them and using the stun to back off
• Titan's Wrath resets your auto attack cooldown, try to time this ability directly after landing an attack
• Try not to initiate on using Dredge Line if you can help it
• Dredge Line and Riptide can be very effective tools to run away if needed. While running away cast Riptide and it will slow them as the run into it. Cast Dredge line into terrain and it will pull you towards the terrain, this as saved me more than once.

Have fun playing Nautilus!