Although we have only completed 1 Viking Cruise, we found many of Viking's optional excursions across the 4 continents visited were generally reasonably priced, compared to industry norms.
How many Viking Cruises have you completed and to what locations, where you find the optional excursions more expensive than industry norms?
Yes, we experienced that Viking Excursions were more expensive than comparable tours from private providers - however, this is standard practice throughout the industry and is most likely consistent across all industries. When I managed a shipyard, if the customer wanted us to purchase materials and accept the risk, then we added a percentage to the cost of the materials. When the tour doesn't go well, Viking refund - per our experience in Christchurch. If it is a private tour - good luck, not saying you won't get a refund, but it will take considerably longer than my 3 or 4 minute trip to Guest Services.
When compared to cruise industry norms, we found Viking's optional excursions to be generally cheaper than equivalent tours on Princess, when all costs are converted to CAN $. We found that even when using full size buses, Viking rarely filled the buses, with about 35 being the normal on most tours we completed. Some examples from our recently completed World Cruise:
Hunter Valley (ship's tour) - full day tour with only 4 pax, a guide and a driver. Yes a little more expensive than some available local tours, but when 60 miles from a ship that sails at 17:00, I consider the extra cost cheap insurance.
Blue Mountains - found a local tour operator with a full day tour, at about 25 - 30% less than ship, but they couldn't work around 07:00 docking, or pick up at White Bay. They would have provided a private tour for both of us at twice the cost of the ship.
Egypt - 4 day overland with 24/7 guide, buses, flight, hotel, meals, entrance fees for CAN $1,600 pp. Couldn't find anything from private operator any cheaper. We also considered this one very reasonably priced.
Saigon - 2 day Mekong Delta with bus, meals, hotel, entrance fees, etc CAN $414 pp While I couldn't find anything comparable, I considered the price very reasonable
Cochin - 6 hr city tour and river cruise CAN $79 pp
Malaga - 10 hr tour to Alhambra Palace & Gardens which included timed tickets, lunch, etc for CAN $259. We also found a private vendor at CAN $125, but they required a minimum of 10 people confirmed and paid in full more than 4 months in advance, to purchase the timed tickets
At no ports, including tender ports do Viking restrict non-ship excursion pax from disembarking. In Bay of Islands (tender) we were on a private tour, so went down to the Atrium, per the request. We were accommodated on the first tender.
Getting back to the ship in time - when booking ship's tours, they guarantee the ship waits or the cruise line schedules and pays to get you to the next port. In some ports, especially on our longer cruises, paying the extra for a ship's tour is what I consider cheap insurance. Private tour operators will endeavour to get you back on time, but circumstance outside their control can result in missing the ship. Does it happen - most definitely yes, as I recall my days on the ships receiving calls on the Bridge advising the number of pax not back on board. When visiting our son in Victoria, we met 2 couples waiting for the ship, as they were on a tour in the last Alaska port and missed the ship. Had to fly to Seattle, then Victoria, joining the ship to pack and disembark the following day.
During the planning process, we consider a number of ship and private tours and base the decision on a risk assessment and our interests. When the risk is too high such as considerable distance from the port (visiting Borobudur from Semarang) , crazy traffic (Java, KL, etc) or distance to next port (Nuku Hiva to Tahiti) we are happy to pay the ship a premium, considering the delta as cheap insurance.
I believe the majority of Viking cruisers are well travelled and can make informed decisions regarding ship or private tours. We certainly don't consider Viking's tour marketing as trying to hook us into booking ship excursions exclusively. Since the OP mentioned they have 800 days with HAL, I suggest they are also well travelled and experienced in the pros/cons of various excursions.