I thought this was just some random troll build the first time I seen, but having played against ap sion's in the past I thought what the heck ill try it. Iv played a lot games as Ap sion sence and cant remember having a negative k/d EVER. Good guide +1 Enjoyed reading it

Thank you soo much, I first time picked Sion absentmindedly in a ranked game, quickly pulled up your guide and carried the game.

Two thumbs way up.

Summoner's Insight doesn't work with Ghost or Ignite.

I know this is stale. Buuut. Ghost and Ignite are the Summoner Spells so there is no need for a point in the masteries for Summoners Insight. just put that point into Improved Recall since it's the next best thing. :D Hope that helps Onlookers! AP Sion Rules!

You ask for an arguement for lichbane, the simplest and logical answer is turrets, turrets take dmg from lichbane attacks, and also. it is a turret game

Vayne should be in high priority

Good guide - I went top and eventually got a score of 6/3 in the end. I was owning Wukong in 1v1's and even solo tower dived him, but in teamfights i kind of lost my touch and eventually couldn't get close enough to their team for my shield to explode :( And once i got rid of my 2 only AP skills i didn't have enough sustain AD to be anymore use :/ Great guide but AP Sion is kind of a one trick pony

I still love playing a mean AP Sion, everyone thinks he isn't viable and that AD is the better route. I just love AP what can I say :D

You should seriously update this guide.... just noticed your guide was when Maokai was just out which is so freaken long ago

Not to be an *** or anything but, this guide is pretty awful. Sion is probably the strongest AP caster early-mid game. So buying Rod of Ages is basically setting him up for late game which really defeats the purpose of AP Sion. Also, Sorc shoes aren't the best boots for him. Since his early game is so strong and he can clear waves with 1 shield, you're going to want to roam. You can do this by getting boots of mobility. The preferable early game build would be boots of mobility and 2-3 dorans, once you get this you can push like a monster and gank like a boss. Build should be something similiar to mobility boots(switch to sorc shoes late game), rabadons, DFG, lich bane, next 2 items can vary.

Well nice guide. In fact long long time ago it was this that made me play ap sion when i was lvl 18 summoner! I have played more than 300 ap sion games since then and i feel i can speak a word that counts. When i started to comment i almost wrote a new guide so in order to shorten it i summed things up:
In lane you need speed advantge because people will keep a distance as they do know you have a good nuke (even f***ing nerfed!). So you could either rush the lvl2 boots or use flash/ghost. I'm not sure ghost is that good as still most guys see it as an alarm to back off, even flash away. On the other hand bush-flash-stun-shieldboom+some damage from your co-laner would be a sure kill early game.
I disaggree with enrage. I max it (almost) last. Why spare a lvl from shield or stun? For 25 ad? Surely not. For the passive? Still no. How big can your cs be in a duo lane untill lvl 15?
If your partner is no support it would be maximum 150-200. So what is the deal with 150-200 hp? I usually max it last after shield, stun and 1-2 points in ulti.
As for items i don't use those anymore because in my opinion they are always situational depending both on your team and enemies. On the other hand I have to say that lich bane is really good to skip. If you get it early it can make you a monster in 2v2 or 3v3 gangs which are usual in mid game. For example when a jungler gangs your lane you may not have the option to avoid mellee. If you use lich bane and your stun smart you can turn the difficult sittuation into some easy kills. It's also crazy itam to tower dive! I mean if you have 70% of your helth and the enmy is towerhugging with lees than half hp why not open shield-lich bane hit-stun lich hit again and leave? Nasty.
Finnally i would definatelly change the glyphs for ap/level as they max the flat ones around level 6-7 and the final outcome is 50% more. Really worth it.
Too many disaggreements to vote for you but still thank you for the effort you've put into this guide.

I had to try it multiple times - if ya come from AD Sion you really have to change your tactics even though you command the same green monster...