Glacier de Bionnassay is a stunning alpine glacier in the Mont Blanc massif, offering breathtaking views and challenging hiking opportunities. Accessibility can be difficult, requiring significant physical fitness and mountaineering experience; trails range from moderate to very strenuous. Solo visits are possible for experienced mountaineers, but guided tours are highly recommended due to the glacier's dynamic nature and potential hazards such as crevasses. Seasonal restrictions apply, with the best time to visit being during the summer months (June-September) when the weather is more stable. The cost can vary depending on whether you opt for a guided tour (which includes equipment rental) or hike independently; expect to pay for transportation, potential refuge stays, and any necessary gear. A typical visit can range from a day hike to a multi-day mountaineering expedition, depending on the chosen route and experience level. Be prepared for rapidly changing weather conditions and the need for proper equipment.