To contact Royal Caribbean's Special Needs department dial 1-833-807-7245 tollfree for use the dedicated email  call their general customer service, or fill out their online Guest Special Needs Form on the Royal Caribbean website. Always include your reservation number and sail date in your communication for efficient service. 
Contact Methods : Visit:  How Can I Contact Royal Caribbean Cruise Special Needs

To file a complaint with Royal Caribbean, first report issues onboard to Guest Services or staff, then follow up post-cruise by completing their survey or contacting their Post-Cruise Guest Relations via phone (833-807-7245 in the US) or email  for unresolved matters, and escalate to the CEO  or social media for serious issues, documenting everything. 

How Can I File a Complaint With Royal Caribbean

To do online check-in for Carnival, visit carnival website or call 1-833-807-7245 the Carnival cruise help center tollfree , log in to your account (or create one), and provide guest info, passport/ID details, emergency contacts, and travel plans, setting your port arrival time within 14 days before sailing to get boarding passes and luggage tags, according to sources like the Carnival Cruise Line website and YouTube tutorials. 

How Do I Do Online Check-In on Carnival Cruise Line

To book a Carnival group cruise, use their online search for smaller groups (up to 3 cabins) or contact the Carnival Group Department directly at 1-833-807-7245 tollfree for 8+ cabins (or 5+ in some regions) to get special rates, potential free berths, and assistance with arrangements like dining and parties, or consider a specialist travel agent for expert handling and perks. 

How Can I Book a Group Cruise With Carnival Cruise Line