The miqaat for the people of Yemen who come via the coastal route is Yalamlam, which is known today as al-Sa’diyyah. It is not permissible for the one who passes by it or comes in line with it, intending to do Hajj or ‘Umrah, to pass it without entering ihram. Jeddah is not a miqaat for them; rather it is the miqaat for its inhabitants and for anyone who intends to do Hajj or ‘Umrah and is residing there, or who comes to it without the intention of doing Hajj or ‘Umrah, then decides to do Hajj.
And Allah is the source of strength; may Allah send blessings and peace upon our Prophet Muhammad and his family and Companions. End quote.
Standing Committee for Academic Research and Issuing Fatwas.
Shaykh ‘Abd al-‘Azeez ibn ‘Abd-Allaah ibn Baaz, Shaykh ‘Abd al-Razzaaq ‘Afeefi, Shaykh ‘Abd-Allaah ibn Ghadyaan, Shaykh ‘Abd-Allaah ibn Qa’ood
Fataawa al-Lajnah al-Daa’imah, 11/134
See also the answer to question number 107988.