First of all, you might not need the tabular environment in your code.
I will supply three solutions for you, which are only different in how they handle pagebreaks:
minipage: they won't be broken over pages
paracol: they will be broken independently and stay in their column
multicols: they will be broken into the next column (from left to right)
Here's an MWE with all of them and your sample code.
\documentclass[10pt]{article}
\usepackage[a5paper, landscape]{geometry} % demo only
\usepackage{lipsum} % demo only
\usepackage{marvosym} % For cool symbols.
\usepackage{hyperref}
\usepackage{paracol}
\usepackage{multicol}
\begin{document}
\lipsum[2-4]
\begin{minipage}[t]{0.33\textwidth}
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\end{minipage}
\begin{minipage}[t]{0.33\textwidth}
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\end{minipage}
\begin{minipage}[t]{0.33\textwidth}
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\end{minipage}
\lipsum[5-6]
\begin{paracol}{3}
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\switchcolumn
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\switchcolumn
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\end{paracol}
\lipsum[8-9]
\begin{multicols}{3}
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\vfill\columnbreak
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\vfill\columnbreak
Prof.\ X Y\\
Place A\\
Location B\\
Country and Postcode\\
\Telefon\ +00 1 234 5678\\
\Letter\ \href{mailto:X@A.ac.jp}{X\textrm{@}A.ac.jp}
\end{multicols}
\lipsum[10]
\end{document}
PS: You should not use \\ for vertical spacing: use \vskip or \vspace instead.