Here is what Irenaeus writes in Against Heresies, Book 3;
But Polycarp also was not only instructed by apostles, and conversed with many who had seen Christ, but was also, by apostles in Asia, appointed bishop of the Church in Smyrna, whom I also saw in my early youth, for he tarried a very long time, and, when a very old man, gloriously and most nobly suffering martyrdom, departed this life, having always taught the things which he had learned from the apostles
And in the Letter to Florinus;
I seem to hear him now relate how he conversed with John and many others who had seen Jesus Christ, the words he had heard from their mouths.
John the disciple of our Lord, and by other apostles with whom he [Polycarp] had been conversant.