Praise be to Allah.
Whoever comes to Makkah for ‘umrah during the months of Hajj and intends to stay there until the time of Hajj is doing Hajj tamattu‘ and therefore must offer a sacrifice.
The intention (niyyah) for tamattu‘, as explained by the scholars, is when a person does ‘umrah during the months of Hajj and – at the time of doing ‘umrah – also intends to do Hajj in the same year. Whoever does that is doing tamattu‘.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
If you enter ihram for ‘umrah during the months of Hajj, having intended to also perform Hajj in the same year, then you are doing tamattu‘, so long as you do not go back to your own city. But if you go back to your city, then come back from your city and enter ihram for Hajj on its own, then you are not doing tamattu‘, so you do not have to offer a hadiy.
End quote from Majmoo‘ Fataawa al-‘Uthaymeen (24/191)
He also said:
So long as you came from your country, intending to do Hajj, and you entered ihram for ‘umrah during the months of Hajj, then you are doing tamattu‘ regardless of whether or not you intended to do tamattu‘, because what you have done is tamattu‘.
End quote from Majmoo‘ Fataawa al-‘Uthaymeen.
He (may Allah have mercy on him) was asked:
I came in Ramadan to perform ‘umrah and I intended to remain there until Hajj. On the fourth day of Shawwaal I did ‘umrah on behalf of my deceased sister. Please note that I was not aware that the one who does ‘umrah during the months of Hajj is regarded as doing tamattu‘. Do I have to offer a hadiy now, because I am doing tamattu‘?
The shaykh replied: The one who does tamattu‘ is the one who enters ihram for ‘umrah during the months of Hajj, after the month of Shawwaal begins, with the intention of doing Hajj in the same year, then he does Hajj. The one who is doing tamattu‘ must offer whatever hadiy he can afford, such as a sheep, a goat or a lamb that is older than six months and is free of any defects that would prevent it from being acceptable as a sacrifice. If you are not able to do that, then you must fast for three days during Hajj and seven days after you return home, making a total of ten. The three days during hajj begin from the time the pilgrim enters ihram for ‘umrah. In other words, for example, a person may do tamattu‘ now, when he has no money. In this case we say: Fast from now; fast three days during Hajj and seven days when he goes back to his family and his journey is over. And if he says: I cannot fast on consecutive days, we say: Let him fast for one day and not fast for one or two days. The evidence for that is the verse in which Allah says (interpretation of the meaning): “then a fast of three days during hajj” [al-Baqarah 2:196]; He did not stipulate that they be consecutive. If Allah had wanted us to fast these days consecutively, He would have stated that. And if a person says: I cannot fast, because I have diabetes and I need water, and I cannot fast for three days or even for one day, then in that case he does not have to do anything, because Allah, may He be glorified and exalted, says (interpretation of the meaning): “Allah does not charge a soul except [with that within] its capacity” [al-Baqarah 2:286].
End quote from Majmoo‘ Fataawa al-‘Uthaymeen (22/42).
Shaykh Ibn ‘Uthaymeen also said:
Should he say, “Labbayk ‘umaratan mutamatti‘an biha ila al-hajj [Here I am for ‘umrah, joining it to Hajj (tamattu‘)]”?
The answer is: No, there is no need for him to say this, because simply intending to do Hajj in the same year is in effect tamattu‘. Tamattu‘ means entering ihram for ‘umrah during the months of Hajj, and finishing it [and exiting ihram], then entering ihram [again] for Hajj in the same year. There is no need to say “joining it to Hajj”. Rather the pilgrim should simply say “Labbayka ‘umratan [Here I am for ‘umrah], and if he has the intention of doing Hajj, this is tamattu‘.
End quote from Jalasaat al-Hajj.