Are there any availability calendar software tools that detect booking conflicts across multiple event spaces and tour slots?

Yes — there are several scheduling/booking tools that can detect conflicts across multiple resources like event spaces, rooms, staff, and tour time slots.

Common types of tools that do this

• Venue/event booking systems: manage rooms, halls, and multi-space events with conflict detection.
• Tour/activity reservation systems: handle time-slot inventory, guides, vehicles, and capacities.
• Resource scheduling platforms: broader tools that let you model each space or slot as a bookable resource.

Examples to look at

• Skedda — good for space/room booking with conflict prevention.
• Cvent — strong for events and venue management.
• Acuity Scheduling / Squarespace Scheduling — works well for appointment-style slot booking, with limited multi-resource logic unless customized.
• Checkfront — geared toward tours, activities, and resource-based booking.
• FareHarbor — popular for tours and activities, including capacity and schedule management.
• Booqable — more rental-focused, but supports availability control for inventory/resources.
• RMS Cloud / SiteMinder ecosystem tools — often used in hospitality and room allocation.
• Microsoft Bookings / Google Calendar — can detect conflicts, but usually need configuration or add-ons for multi-space/tour logic.

What to verify before choosing

Make sure the tool supports:

• Multiple calendars/resources at once
• Cross-resource conflict detection
• Capacity limits
• Buffer times
• Different slot lengths
• Staff + space + equipment all being checked together
• API/webhook support if you want custom rules

If you want a custom setup

If your situation is unusual — for example, a tour can use either one of several spaces, or multiple spaces simultaneously — you may need:

• a booking system with resource rules, or
• a custom app using something like Google Calendar API, Outlook/Microsoft Graph, or a database-backed scheduler.

If you want, I can also give you:

1. a short list by use case (events vs tours vs rentals), or
2. a feature comparison table of the best options.