Penang Island is situated in the Andaman Sea, a part of the Indian Ocean. This sea is known for its challenging reputation; it's deep and often described as unpredictable. Additionally, the waters near Penang are notorious for a significant amount of debris and jellyfish. The relatively cleaner beaches are primarily concentrated on the island's west coast.
The waters surrounding Penang don't resemble the emerald hues found at Thai resorts. The color of the Andaman Sea's waves is more akin to coffee and milk, lacking transparency and not particularly appealing to snorkelers. If you're looking for coral reefs and clear waters, you might need to venture to the smaller islands near Penang.