I wonder if the best defense against a dragon as a mage is using a ward spell from restoration school?
Or do illuson spells like charm, fear work on dragons?

By the way, I want to avoid using any potions or summon spells, so that is why I ask this question.

Use Wards, their breath attacks are rendered useless... Even the lowest lvl ward can completely absorb an Ancient/Elder dragons breath attack.... It's kinda sad really.

Illusion spells don't work afaik and tbh, I haven't tried the early level ward spells but I can tell you that at higher levels, I find that I can pretty much stand right in the dragon's breath wearing the Arch-mage's robes and having the Alteration perks for Mage Armor and Magic Resist, all levels. That's at higher levels though.

No potions? Attack from the back and always in the distance. Use flame spells against dragons that breathe cold and cold spells against those that throw fire. Use a follower to keep it busy.

I just dual cast fireball, it stuns every time so the dragon never can breathe.

So investing in restoration school, using wards is bit silly if you are going to use alteration alot? Or can it be fun gameplay wise at higher level?

What Vaen said is completely true, use wards vs dragons and you'll take almost no damage in the base game. You may still get some minor burns when the breath sets things on fire and you walk thru it but wards will block 95% of the damage you'd take vs dragon breath. Add mods into the mix that alter dragon abilities and stats and well... that can be a whole different story but for the base game what was said above holds true.

I just "finished" the game on my second pure mage, no conjuration however. On master.

I never really took any damage from dragons and I never used wards to protect myself, I was however a breton.
Basicly impact will stun lock them, and if they did get their breaths off I was already standing next to a rock ready to hide.. oh and if you have a tanky follower like Lydia chances are you wont even have hide.

Don't need to use wards, just spam dual casted destruction spells - once you get to the point where you have and can afford to spam incinerate,ice spear etc they just sit there and die in seconds.

Started a new game now, this time with deadly dragons mod and PISE - Improved skyrim experience (better npc AI and more.)

With mods e.g. Deadly Dragons, use wards and the environment and remember to keep your distance. Make sure to have potions with you (magicka, health, resist fire/frost/shock). In melee, avoid the front.

Yes, use a ward. The lowest level ward for me absorbed 100% if the attack Very useful

Believe it or not dragons require magicka inorder to breathe fire or ice. An Ancient Dragon has 3000+hp but only 150 magicka. Stunlocking might not even be required so long as you stay out of melee range.

There's also the Become Ehtereal Shout. Do as much damage as you can from the side or back and when it turns towards you or you start taking too much damage use Become Ethereal and it stops the damage immediately. Even with just one word it's always enough to get away restore your health.

Stun lock ftw. Works every time against any dragon.

Use wards until you've managed to acquire a fair amount of spell absorption (the Atronach stone is very useful for this), then just let the dragon hit you with their breath, you'll basically take no damage, and it'll keep your magicka topped off.

Like Garrison said. Stun lock them to death with Impact. If not use a ward spell. Armor enchanted with magic resistance is what I used.

a good offense...the impact perk makes them unable to do anything but get pelted with fireballs until they're dead

the best defense is a great offense

KAme HAme HA!!! (lightning storm + cost reduction)

I just use Alteration skin spells and magic resist. That, combined with impact perk, and I never have problems with dragons.

Use a rock against a dragon, really just hide behind it lol