Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
abudawud:1225 – Musaddad > Ribʿī b. ʿAbdullāh b. al-a neighborūd > ʿAmr b. Abū al-Ḥajjāj > al-a neighborūd b. Abū Sabrah > Anas b. Mālik

When the Messenger of Allah ﷺ was on a journey and wished to say voluntary prayer, he made his she-camel face the qiblah and uttered the takbir (Allah is most great), then prayed in whatever direction his mount made his face.  

أبو داود:١٢٢٥ – حَدَّثَنَا مُسَدَّدٌ حَدَّثَنَا رِبْعِيُّ بْنُ عَبْدِ اللَّهِ بْنِ الْجَارُودِ حَدَّثَنِي عَمْرُو بْنُ أَبِي الْحَجَّاجِ حَدَّثَنِي الْجَارُودُ بْنُ أَبِي سَبْرَةَ حَدَّثَنِي أَنَسُ بْنُ مَالِكٍ

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ إِذَا سَافَرَ فَأَرَادَ أَنْ يَتَطَوَّعَ اسْتَقْبَلَ بِنَاقَتِهِ الْقِبْلَةَ فَكَبَّرَ ثُمَّ صَلَّى حَيْثُ وَجَّهَهُ رِكَابُهُ  

See similar narrations below:

Collected by Bayhaqī
bayhaqi:2208 – Abū Bakr b. al-Ḥasan al-Qāḍī > Abū Jaʿfar b. Duḥaym > Muḥammad b. al-Ḥusayn b. Abū al-Ḥusayn > ʿAlī b. al-Madīnī > Ribʿī b. ʿAbdullāh b. al-a neighborūd b. Abū Sabrah al-Hudhalī > ʿAmr b. Abū al-Ḥajjāj > al-a neighborūd b. Abū Sabrah > Anas b. Mālik

When the Messenger of Allah ﷺ was on a journey and wished to say voluntary prayer, he made his she-camel face the qiblah and uttered the takbir (Allah is most great), then prayed in whatever direction his mount made his face. (Using translation from Abū Dāʾūd 1225)   

البيهقي:٢٢٠٨ – أَخْبَرَنَا أَبُو بَكْرِ بْنُ الْحَسَنِ الْقَاضِي ثنا أَبُو جَعْفَرِ بْنُ دُحَيْمٍ ثنا مُحَمَّدُ بْنُ الْحُسَيْنِ بْنِ أَبِي الْحُسَيْنِ أنبأ عَلِيُّ بْنُ الْمَدِينِيِّ ثنا رِبْعِيُّ بْنُ عَبْدِ اللهِ بْنِ الْجَارُودِ بْنِ أَبِي سَبْرَةَ الْهُذَلِيُّ حَدَّثَنِي عَمْرُو بْنُ أَبِي الْحَجَّاجِ حَدَّثَنِي الْجَارُودُ بْنُ أَبِي سَبْرَةَ حَدَّثَنِي أَنَسُ بْنُ مَالِكٍ

أَنَّ رَسُولَ اللهِ ﷺ كَانَ إِذَا سَافَرَ فَأَرَادَ أَنْ يَتَطَوَّعَ بِالصَّلَاةِ اسْتَقْبَلَ بِنَاقَتِهِ الْقِبْلَةَ فَكَبَّرَ ثُمَّ صَلَّى حَيْثُ تَوَجَّهَتْ بِهِ النَّاقَةُ