How can I cast spells in melee without provoking Attacks of Opportunity?

Question

Now I know that casting a spell with Somatic or Material component does trigger an Attack of Opportunity.
So how can I cast Vampiric Touch¹ on a Fighter without provoking? The spell has range of touch, so I have to be adjacent, and it has a somatic component.

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1) Vampiric Touch is just an example, but any spell could be there instead with a range of touch and somatic component

Answer 1

Here are four options:

1. Wait for them to spend their reaction first, or cause it to be spent on something or someone else before casting.

2. Use the reach metamagic.

3. If you have a familiar, use Spell Delivery to deliver the spell.

4. Some conditions can prevent your being targeted by the ability, such as giving the Fighter the unconscious condition, or you having the undetected condition.

Unfortunately although the Eschew Materials feat removes the need for materials that don't have a cost, it doesn't actually remove the Material trait, so wouldn't work to prevent Attacks of Opportunity on spells that would otherwise only gain the manipulate trait via their Material component.