Yes. Strong form /ɪz/ in both UK and US English: the short i vowel of sit plus a buzzing z. Stress that vowel only in this deliberate strong form.
In fast, unstressed speech the weak forms /z/ or /s/ drop the vowel entirely; both are valid alternatives.
Mouth cues
Drop your jaw slightly and spread your lips a little. Aim for the short vowel of sit, not the longer vowel of seat.
Say that vowel, then lift the front of your tongue close to the ridge behind your top teeth and hum a z. Keep your voice on; it should buzz.
Join them as one beat: ih-z. Say it slowly twice, then smoothly twice more, keeping the vowel short.
Contrast check: is beside eaves. The first starts with the sit vowel plus z; the second starts with the seat vowel. Keep your jaw lower for is.
Say it in a phrase
Strong form first: /ɪz/. Say the short i vowel of sit, then a buzzing z. That is the full pronunciation of is.
Say this phrase, letting is take its full strong form: This is my seat. Keep the vowel short and let the z buzz through.
In fast, unstressed speech you may hear only z or s with no vowel at all, as in She's here. That weak form is valid, not an error.
Ready to test the sound in a sentence of your own? Try the quick practice below.