A measurement of the $$ B_{s}^{0} \rightarrow J/\psi \phi $$ $B_s^0\to J/\psi \varphi$ decay parameters using $$ 80.5\, \mathrm {fb^{-1}} $$ $80.5{\mathrm{fb}}^{-1}$ of integrated luminosity collected with the ATLAS detector from 13 $$\text {Te}\text {V}$$ $\text{Te}$ proton–proton collisions at the LHC is presented. The measured parameters include the CP-violating phase $$\phi _{s} $$ ${\varphi }_s$ , the width difference $$ \Delta \Gamma _{s}$$ $\Delta {\Gamma }_s$ between the $$B_{s}^{0}$$ $B_s^0$ meson mass eigenstates and the average decay width $$ \Gamma _{s}$$ ${\Gamma }_s$ . The values measured for the physical parameters are combined with those from $$ 19.2\, \mathrm {fb^{-1}} $$ $19.2{\mathrm{fb}}^{-1}$ of 7 and 8 $$\text {Te}\text {V}$$ $\text{Te}$ data, leading to the following: $$\begin{aligned} \phi _{s}= & {} -0.087 \pm 0.036 ~\mathrm {(stat.)} \pm 0.021 ~\mathrm {(syst.)~rad} \\ \Delta \Gamma _{s}= & {} 0.0657 \pm 0.0043 ~\mathrm {(stat.)}\pm 0.0037 ~\mathrm {(syst.)~ps}^{-1} \\ \Gamma _{s}= & {} 0.6703 \pm 0.0014 ~\mathrm {(stat.)}\pm 0.0018 ~\mathrm {(syst.)~ps}^{-1} \end{aligned}$$ $\begin{array}{cc}{\varphi }_s=& -0.087\pm 0.036(\mathrm{stat}.)\pm 0.021(\mathrm{syst}.)\mathrm{rad}\\ \Delta {\Gamma }_s=& 0.0657\pm 0.0043(\mathrm{stat}.)\pm 0.0037{(\mathrm{syst}.)\mathrm{ps}}^{-1}\\ {\Gamma }_s=& 0.6703\pm 0.0014(\mathrm{stat}.)\pm 0.0018{(\mathrm{syst}.)\mathrm{ps}}^{-1}\end{array}$ Results for $$\phi _{s} $$ ${\varphi }_s$ and $$ \Delta \Gamma _{s}$$ $\Delta {\Gamma }_s$ are also presented as 68% confidence level contours in the $$\phi _{s} $$ ${\varphi }_s$ – $$ \Delta \Gamma _{s}$$ $\Delta {\Gamma }_s$ plane. Furthermore the transversity amplitudes and corresponding strong phases are measured. $$\phi _{s} $$ ${\varphi }_s$ and $$ \Delta \Gamma _{s}$$ $\Delta {\Gamma }_s$ measurements are in agreement with the Standard Model predictions.