
Patch 7.3a

Favorable matchup
Fiora can turn Volibear's engage into an opportunity: Riposte answers his stun and Vitals punish his health. The key is a short trade, not standing in front of his second bite.
Volibear's threat lies in the hit of his first ability. Save Riposte for the impact: if you block that crowd control and the thrust reaches Volibear, you can stun him. Casting it as soon as he starts running lets him wait it out and hit you afterward.
Hitting a Vital grants max-health true damage, healing and movement speed to get out. That lets you step in from an angle, strike and back off. You don't need to push through his third ability's shield in a head-on duel to get value.
Look for a Vital once Volibear has used his third ability or can't complete another bite. If you land Riposte on the stun, use that crowd control to strike and exit to the side.
As Volibear, fake your engage and delay the hit if Fiora still has Riposte. Protect the Vital side with your positioning and use the lightning circle to make it harder for her to circle you. When Riposte misses, look for a trade without chasing her into a bad wave.

Favorable matchup
Jax has a direct answer to the attack side of Volibear's kit: Counter Strike. He can deny basic attacks, stun and back off, but he shouldn't treat that defense as immunity to the bite, the lightning or the ultimate.
During Counter Strike, Jax dodges basic attacks and can close the window with a stun. That lowers the value of an engage built on hitting repeatedly. The defense is no license to stay inside the lightning or ignore the damage from his other abilities.
Your first ability lets you close in once your opponent has spent resources, or retreat toward an available allied unit. Holding it helps you end the trade before Volibear chains more damage and healing; always leaping onto him throws that exit away.
Trade when you have Counter Strike and a leap out. If Volibear drops his third ability under your feet, leave the circle first; hit him again once his shield stops protecting him.
As Volibear, wait for Counter Strike to end before pressing with basic attacks. Use the lightning to force Jax to move and don't hand him a stun followed by a free retreat. His leap has defensive value: punish him when he uses it forward with no unit to jump back to.

Execution matters
Teemo can frustrate Volibear with range, poison and blind. His edge needs space: if Volibear manages to corner him or sets up an engage with his jungler, Teemo is fragile and his blind doesn't stop the whole combo.
Teemo's first ability makes it harder for Volibear to get value from his basic attacks while blinded. Use it when he is about to attack, not just to add damage to your poke. It doesn't remove the damage of his bite or turn the circle of his third ability into a safe zone.
Poisoned attacks let you punish every step he takes toward a minion. Teemo's second ability gives mobility to keep your distance, and mushrooms make a chase along known routes harder. That edge disappears if you push without vision and get closed off from two sides.
Poke when Volibear goes to last-hit a minion and can't reach you with his first ability. If he starts his charge, get blind and your retreat ready; don't step forward again while he can still land his engage.
As Volibear, don't give up health chasing every one of Teemo's basic attacks. Wait for him to spend blind or his mobility, clear mushroom routes and look to approach from an angle where his vision is denied. A coordinated engage is more reliable than running in a straight line through his prepared zone.