The Catechism in Questions & Answers

185. Are there any witnesses to the resurrection of Christ?

The resurrection of Jesus Christ occurred without any human witness to the event. Nevertheless, the resurrection of the Son of God is attested in many places in Holy Scripture. One such testimony is the empty tomb. Other evidence includes the various appearances of the Risen One over the 40 days between His resurrection and ascension: these are specifically named individuals to whom He showed Himself and who recognised Him.
The resurrection of Jesus Christ is not wishful thinking on the part of His followers, but a real event. It did indeed occur.

“For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures, and that He was buried, and that He rose again the third day according to the Scriptures, and that He was seen by Cephas, then by the twelve. After that He was seen by over five hundred brethren at once, of whom the greater part remain to the present, but some have fallen asleep. After that He was seen by James, then by all the Apostles.”
1 Corinthians 15: 3-7