Answer: "Allāhu akbar, allāhu akbar, allāhu akbar" (Allah is the Most Great - three times), "Subhāna al-ladhī sakhkhara lanā hādha wa mā kunnā lahu muqrinīn wa innā ilā rabbinā lamunqalibūn" (Glory be to Him Who has subjected this for us, for we could not have done it by ourselves. It is to our Lord that we will surely return), "Allāhumma innā nas’aluka fī safarinā hādha al-birra wat-taqwā wa min al-‘amali mā tardā, allāhumma hawwin ‘alaynā safaranā hādha watwi ‘annā bu‘dah, allāhumma anta as-sāhibu fis-safar wa al-khalīfatu fil ahl, allāhumma innī a‘ūdhu bika min wa‘thā’ as-safar wa ka’ābat al-manzhar wa sū’ il-munqalab fil māli wal ahl" (O Allah, we ask You on this journey of ours for goodness and piety, and for deeds that are pleasing to You. O Allah, make easy this journey for us and make its distance short for us. O Allah, You are the Companion on the journey and the One in Whose care we leave our family behind. O Allah, I seek refuge in You from this journey's hardships, and from the terrible sights in store and from a misfortunate return to our property and our family).

On returning, one should say the same and add the following:

"Āyibūn tā’ibūn ‘ābidūn lirabbinā hāmidūn" (We are returning in safety, turning to our Lord in repentance, worshiping Him, and praising Him). [Narrated by Muslim]