Guests are unwelcome. Is it passive or active? The verb here is tranisitive and the guests aren't the one that unwelcomes.
“Are’ is the verb used in this sentence.Hence this sentence belongs to Present Tense.
It is not in:
Continuous tense, prefect tense or perfect continuous tense.Hence it is in Simple Present Tense and in affirmative form.
Formula for this sentence in Passive voice is as follow:
Subject+ helping verb + Past participle.+................
Note: This is no past participle form of the verb ‘unwelcome’.
Hence it is not in passive voice.