Using e+e− annihilation data sets corresponding to an integrated luminosity of 4.5 fb−1, collected with the BESIII detector at center-of-mass energies between 4.600 and 4.699 GeV, we report the first measurements of the absolute branching fractions B(Λc+→pKL0)=(1.67±0.06±0.04)%, B(Λc+→pKL0π+π−)=(1.69±0.10±0.05)%, and B(Λc+→pKL0π0)=(2.02±0.13±0.05)%, where the first uncertainties are statistical and the second systematic. Combining with the known branching fractions of Λc+→pKS0, Λc+→pKS0π+π−, and Λc+→pKS0π0, we present the first measurements of the KS0-KL0 asymmetries R(Λc+,KS,L0X)=B(Λc+→KS0X)+B(Λc+→KL0X)B(Λc+→KS0X)−B(Λc+→KL0X) in charmed baryon decays: R(Λc+,pKS,L0)=−0.025±0.031, R(Λc+,pKS,L0π+π−)=−0.027±0.048, and R(Λc+,pKS,L0π0)=−0.015±0.046. No significant asymmetries within the uncertainties are observed.