The European Council for Fatwa and Research has issued the following: “Regarding a woman’s travel without a mahram, this is primarily unlawful according to the hadith of the Prophet (peace and blessings be upon him): “A woman who believes in Allah and the Hereafter shall not travel for (a period of) a day and a night unless accompanied by a mahram of hers.” (Reported by al-Bukhari and Muslim)
Depending on this general text, some scholars are of the opinion that a woman should not travel by herself. Other scholars stipulate that her travel is permissible in the company of a trustworthy group of men or men and women. The prohibition conveyed by the hadith is justified by fearing that the woman may be exposed to mischief or temptation if she travels alone, bearing in mind that the dangers of travel were numerous in the past. Caliph `Umar ibn al-Khattab (may Allah be pleased with him) allowed the Prophet’s wives (Mothers of the Believers) to travel for Hajj with a group of believers and sent with them `Uthman ibn `Affan and `Abdul-Rahman ibn `Auf.
In the hadith of the Prophet (peace and blessings be upon him) to `Adiy ibn Hatim we read: “If you live long, you will see the woman travel from Hirah (a city in Iraq ) to circumambulate the Ka`bah fearing none but Allah.” (Reported by al-Bukhari)
this confirms that the cause (of the prohibition) is fear (of insecurity). If security is guaranteed and fear is no more present, a woman may travel, particularly nowadays when travel has become easy, whether by air, train or coach. In all these means of transportation, company is available and security is realized for the Muslim woman.
This is in respect of the woman’s travel from one town to another or from one country to another and her arrival on the same day of her travel, whereupon she finds company providing security. If the journey requires staying overnight in a hotel on the way, or the journey is intended to perform a certain task that requires residence for a certain period, the woman, in this case, is supposed primarily to travel with a mahram of hers, or reside for the required period with a Muslim family in that country to avoid the likelihood of temptation or mischief the woman may face.”