Yes, a day trip from Lake Como to Lugano, Switzerland, is very easy and highly recommended due to the short distance and efficient transport links. The fastest and most convenient method is the train from Como San Giovanni to Lugano, which takes only about 34 to 40 minutes and runs every 30 minutes. The journey is incredibly scenic, passing through the base of the Alps. If you are staying in the mid-lake region (Bellagio or Varenna), you can take a ferry to Menaggio and then catch a direct bus to Lugano, which takes roughly one hour. Since Lugano is in the Swiss canton of Ticino, you will be crossing an international border; while it is usually a "soft" border within the Schengen Area, you should always carry your passport. Once in Lugano, you can enjoy the Mediterranean-style Swiss architecture, the beautiful Parco Ciani, and perhaps take the funicular up to Monte San Salvatore for panoramic views of the lake. It is a perfect contrast to the Italian side, offering a blend of Swiss efficiency and Italian-influenced culture that can be easily explored and returned from in a single 8-hour window.