Wlazły played in Skra Bełchatów for over 10 years. During that time he won eight titles of the Polish Champion (2005, 2006, 2007, 2008, 2009, 2010, 2011, 2014). With PGE Skra, he won a bronze medal at the 2007–08 CEV Champions League, and was also individually awarded as the "Best Spiker" of the tournament. He won a bronze medal at the 2009–10 CEV Champions League, playing with Skra Bełchatów and was awarded as the "Best Scorer". Mariusz win a silver medal and the Most Valuable Player award in the &lt;a href="2011%E2%80%9312%20CEV%20Champions%20League"&gt;CEV Champions League 2011/2012&lt;/a&gt;. He has two silver medals from the Club World Championships in 2009 and 2010, and one bronze medal in 2012. In 2014, he won his 8th title of the Polish Champion with Skra. On 8 October 2014, his team won the Polish SuperCup . His club played in the Final four of the 2014–15 CEV Champions League, but lost in the semifinal to Asseco Resovia, and in a match for third place to Berlin Recycling Volleys, and did not achieve any medal. In May 2015, he signed a contract with Qatari club Al Arabi Doha for the duration of the Emir Cup (only 2 matches). All the money earned in Qatar, Mariusz Wlazły decided to transfer to his own foundation. On 7 February 2016, he won the Polish Cup after beating ZAKSA in the final.